Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Measurement Date	October 31
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Noncurrent assets	$ 33,757,000	$ 28,258,000
Amounts Not Yet Recognized as a Component of Cost and Recognized in a Deferred Regulatory Account
Regulatory asset	(213,867,000)	(246,306,000)
Defined Benefit Plan Actuarial Gains And Losses Amortization Corridor	5 years
Gains And Losses Amortized In Excess Of Percentage	10.00%
Qualified Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, General Information	We have a noncontributory, tax-qualified defined benefit pension plan (qualified pension plan) for our eligible employees. A defined benefit plan specifies the amount of benefit that an eligible participant eventually will receive upon retirement using information about that participant. An employee became eligible on the January 1 or July 1 following either the date on which he or she attained age 30 or attained age 21 and completed 1,000 hours of service during the 12-month period commencing on the employment date. Plan benefits are generally based on credited years of service and the level of compensation during the five consecutive years of the last ten years prior to retirement or termination during which the participant received the highest compensation. Our policy is to fund the plan in an amount not in excess of the amount that is deductible for income tax purposes. The qualified pension plan is closed to employees hired after December 31, 2007. Employees hired prior to January 1, 2008 continue to participate in the qualified pension plan. Employees are vested after five years of service and can be credited with up to a total of 35 years of service. When a vested employee leaves the company, his benefit payment will be calculated as the greater of the accrued benefit as of December 31, 2007 under a specific formula plus the accrued benefit calculated under a second formula for years of service after December 31, 2007, or the benefit for all years of service up to 35 years under the second formula.
Standard Eligibility Age For Defined Benefit Plan	30 years
Service Required For Eligibility In Defined Benefit Plan	125 days
Years Of Highest Compensation For Benefit Calculation	5 years
Duration To Complete Service Requirement	12 months
Horizon For DBPP Long Term Rates Of Return	20 years
Period Of Compensation For Benefit Calculation	10 years
Plan Vesting Period Defined Benefit Plan	5 years
Maximum Credited Service Period	35 years
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Defined Benefit Plan, Fair Value of Plan Assets	336,443,000	300,661,000	272,337,000
Defined Benefit Pension Plan Funding Target	100.00%
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	10,000,000
Reconciliation Of Changes In Plan Benefit Obligations And Fair Value Of Assets [Abstract]
Accumulated Benefit Obligation At Year End	252,706,000	230,175,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	272,403,000	293,327,000
Service cost	10,865,000	12,005,000	9,573,000
Interest cost	11,781,000	9,946,000	10,640,000
Plan amendments	0	0
Actuarial (gain) loss	23,646,000	(24,859,000)
Participant contributions	0	0
Administrative expenses	(465,000)	(534,000)
Benefit payments	(15,544,000)	(17,482,000)
Obligation at end of year	302,686,000	272,403,000	293,327,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	300,661,000	272,337,000
Actual return on plan assets	31,791,000	26,340,000
Employer contributions	20,000,000	20,000,000
Participant contributions	0	0
Administrative expenses	(465,000)	(534,000)
Benefit payments	(15,544,000)	(17,482,000)
Fair value at end of year	336,443,000	300,661,000	272,337,000
Funded status at year end - (under) over	33,757,000	28,258,000
Noncurrent assets	33,757,000	28,258,000
Current liabilities	0	0
Noncurrent liabilities	0	0
Net amount recognized	33,757,000	28,258,000
Amounts Not Yet Recognized as a Component of Cost and Recognized in a Deferred Regulatory Account
Unrecognized transition obligation	0	0
Unrecognized prior service (cost) credit	15,046,000	17,243,000
Unrecognized actuarial loss	(103,038,000)	(96,338,000)
Regulatory asset	(87,992,000)	(79,095,000)
Cumulative employer contributions in excess of cost	121,749,000	107,353,000
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	10,865,000	12,005,000	9,573,000
Interest cost	11,781,000	9,946,000	10,640,000
Expected return on plan assets	(22,530,000)	(21,105,000)	(20,289,000)
Transition obligation	0	0	0
Amortization of prior service cost (credit)	(2,198,000)	(2,198,000)	(2,198,000)
Amortization of net loss	7,685,000	11,202,000	5,966,000
Net periodic benefit cost	5,603,000	9,850,000	3,692,000
Estimated Amortization And Expected Refunds [Abstract]
Amortization of unrecognized prior service cost (credit)	(2,198,000)
Amortization of unrecognized actuarial loss	8,121,000
Other Changes In Plan Assets And Benefit Obligatin Recognized Through Regulatory Asset Or Liability [Abstract]
Prior service cost	0	0	0
Net loss (gain)	14,385,000	(30,094,000)	43,945,000
Amounts Recognized As Component Of Net Periodic Benefit Cost [Abstract]
Transition obligation	0	0	0
Amortization of net loss	(7,685,000)	(11,202,000)	(5,966,000)
Amortization of prior service (cost) credit	2,198,000	2,198,000	2,198,000
Total recognized in regulatory asset (liability)	8,898,000	(39,098,000)	40,177,000
Total Recognized In Net Periodic Benefit Cost And Regulatory Asset (Liability)	14,501,000	(29,248,000)	43,869,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate	4.13%	4.55%
Rate Of Compensation Increase	3.68%	3.72%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount Rate	4.55%	3.51%	4.67%
Expected Long Term Rate Of Return On Plan Assets	7.75%	8.00%	8.00%
Rate Of Compensation Increase	3.72%	3.76%	3.78%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2015	29,946,000
2016	16,794,000
2017	16,332,000
2018	19,197,000
2019	20,685,000
2020 - 2024	110,459,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	300,661,000	272,337,000
Actual return on plan assets:
Fair value at end of year	336,443,000	300,661,000	272,337,000
Qualified Pension [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Standard Eligibility Age For Defined Benefit Plan	21 years
Qualified Pension [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	8.00%	2.00%
Defined Benefit Plan, Fair Value of Plan Assets	28,367,000	5,722,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	28,367,000	5,722,000
Actual return on plan assets:
Fair value at end of year	28,367,000	5,722,000
Qualified Pension [Member] | Fixed Income Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	45.00%
Defined Benefit Plan, Actual Plan Asset Allocations	45.00%	38.00%
Qualified Pension [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	8.00%	8.00%
Defined Benefit Plan, Fair Value of Plan Assets	27,224,000	24,078,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	27,224,000	24,078,000
Actual return on plan assets:
Fair value at end of year	27,224,000	24,078,000
Qualified Pension [Member] | Long Duration Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	14.00%	11.00%
Defined Benefit Plan, Fair Value of Plan Assets	48,049,000	34,041,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	48,049,000	34,041,000
Actual return on plan assets:
Fair value at end of year	48,049,000	34,041,000
Qualified Pension [Member] | Corporate Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	15.00%	14.00%
Defined Benefit Plan, Fair Value of Plan Assets	49,816,000	42,701,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	49,816,000	42,701,000
Actual return on plan assets:
Fair value at end of year	49,816,000	42,701,000
Qualified Pension [Member] | High Yield Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	3.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	8,100,000	14,680,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	8,100,000	14,680,000
Actual return on plan assets:
Fair value at end of year	8,100,000	14,680,000
Qualified Pension [Member] | Common trust fund - Bank loans [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	16,187,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	16,187,000
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	30 days
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	Daily
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Description	None
Actual return on plan assets:
Fair value at end of year	16,187,000
Qualified Pension [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	0.00%	0.00%
Defined Benefit Plan, Fair Value of Plan Assets	1,035,000	1,098,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,035,000	1,098,000
Actual return on plan assets:
Fair value at end of year	1,035,000	1,098,000
Qualified Pension [Member] | Derivatives [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	0.00%	0.00%
Defined Benefit Plan, Fair Value of Plan Assets	(1,000)	(11,000)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	(1,000)	(11,000)
Actual return on plan assets:
Fair value at end of year	(1,000)	(11,000)
Qualified Pension [Member] | Derivatives [Member] | Maximum [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Investment Limitation Percentage	10.00%
Qualified Pension [Member] | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	35.00%
Defined Benefit Plan, Actual Plan Asset Allocations	31.00%	43.00%
Qualified Pension [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	3.00%	4.00%
Defined Benefit Plan, Fair Value of Plan Assets	9,982,000	12,023,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	9,982,000	12,023,000
Actual return on plan assets:
Fair value at end of year	9,982,000	12,023,000
Qualified Pension [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	6.00%	6.00%
Defined Benefit Plan, Fair Value of Plan Assets	19,937,000	16,908,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	19,937,000	16,908,000
Actual return on plan assets:
Fair value at end of year	19,937,000	16,908,000
Qualified Pension [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	6.00%	6.00%
Defined Benefit Plan, Fair Value of Plan Assets	19,745,000	17,823,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	19,745,000	17,823,000
Actual return on plan assets:
Fair value at end of year	19,745,000	17,823,000
Qualified Pension [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	9.00%	10.00%
Defined Benefit Plan, Fair Value of Plan Assets	31,329,000	30,831,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	31,329,000	30,831,000
Actual return on plan assets:
Fair value at end of year	31,329,000	30,831,000
Qualified Pension [Member] | Common Trust Fund International Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations		8.00%
Defined Benefit Plan, Fair Value of Plan Assets		24,460,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year		24,460,000
Actual return on plan assets:
Fair value at end of year		24,460,000
Qualified Pension [Member] | Common Trust Fund International Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	7.00%	9.00%
Defined Benefit Plan, Fair Value of Plan Assets	22,877,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	27,270,000
Fair value at end of year	22,877,000
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	30 days
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	Monthly
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Description	None
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	27,270,000
Actual return on plan assets:
Fair value at end of year	22,877,000
Qualified Pension [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	5.00%
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	16,675,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	15,042,000
Fair value at end of year	16,675,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	15,042,000
Actual return on plan assets:
Fair value at end of year	16,675,000
Qualified Pension [Member] | Total Other Investments [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	15.00%
Defined Benefit Plan, Actual Plan Asset Allocations	11.00%	12.00%
Qualified Pension [Member] | Hedge Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	6.00%	6.00%
Defined Benefit Plan, Fair Value of Plan Assets	19,829,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	18,571,000
Fair value at end of year	19,829,000
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	65 days
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	Quarterly
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Description	Redeemed in whole or part but not less than the minimum redemption amount for each currency. Redemption within one year of purchase is subject to 1.5% redemption fee. Redeemed on “first in first out” basis. None of our investment is subject to the redemption fee. Fund’s Board of Directors may limit or suspend share redemptions until a further notification ending suspension. No such notification has been received as of October 31, 2014.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	18,571,000
Actual return on plan assets:
Fair value at end of year	19,829,000
Qualified Pension [Member] | Private Equity Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	3.50%
Defined Benefit Plan, Actual Plan Asset Allocations	2.00%	2.00%
Defined Benefit Plan, Fair Value of Plan Assets	7,158,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	4,659,000
Fair value at end of year	7,158,000
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Initial Unfunded Subscription Balance	12,000,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	Limited
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	5,400,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Description	Investors have only very limited withdrawal rights for specific legal or regulatory reasons. Any transfer of interest will be subject to approval.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	4,659,000
Actual return on plan assets:
Fair value at end of year	7,158,000
Qualified Pension [Member] | Private Equity Fund of Funds [Member] | Minimum [Member]
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	10 years
Qualified Pension [Member] | Private Equity Fund of Funds [Member] | Maximum [Member]
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	12 years
Qualified Pension [Member] | Commodities Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	3.00%	4.00%
Defined Benefit Plan, Fair Value of Plan Assets	10,134,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	10,765,000
Fair value at end of year	10,134,000
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	35 days
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	Monthly
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Description	Redemption within one year of purchase is subject to 1% redemption fee. None of our investment is subject to the redemption fee. If 95% or more of the balance is requested, 95% of the balance will be paid within 30 days. Any outstanding balance or interest owed will be paid after the annual audit is complete.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	10,765,000
Actual return on plan assets:
Fair value at end of year	10,134,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	40.00%	37.00%
Defined Benefit Plan, Fair Value of Plan Assets	133,748,000	112,879,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	133,748,000	112,879,000
Actual return on plan assets:
Fair value at end of year	133,748,000	112,879,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	27,932,000	5,566,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	27,932,000	5,566,000
Actual return on plan assets:
Fair value at end of year	27,932,000	5,566,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Long Duration Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | High Yield Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	8,100,000	14,680,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	8,100,000	14,680,000
Actual return on plan assets:
Fair value at end of year	8,100,000	14,680,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Common trust fund - Bank loans [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0
Actual return on plan assets:
Fair value at end of year	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Derivatives [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	48,000	6,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	48,000	6,000
Actual return on plan assets:
Fair value at end of year	48,000	6,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	9,982,000	12,023,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	9,982,000	12,023,000
Actual return on plan assets:
Fair value at end of year	9,982,000	12,023,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	19,937,000	16,908,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	19,937,000	16,908,000
Actual return on plan assets:
Fair value at end of year	19,937,000	16,908,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	19,745,000	17,823,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	19,745,000	17,823,000
Actual return on plan assets:
Fair value at end of year	19,745,000	17,823,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	31,329,000	30,831,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	31,329,000	30,831,000
Actual return on plan assets:
Fair value at end of year	31,329,000	30,831,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Common Trust Fund International Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year		0
Actual return on plan assets:
Fair value at end of year		0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Common Trust Fund International Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	16,675,000	15,042,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	16,675,000	15,042,000
Actual return on plan assets:
Fair value at end of year	16,675,000	15,042,000
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Hedge Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Private Equity Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 1 [Member] | Commodities Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	58.00%	61.00%
Defined Benefit Plan, Fair Value of Plan Assets	195,537,000	183,123,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	195,537,000	183,123,000
Actual return on plan assets:
Fair value at end of year	195,537,000	183,123,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	435,000	156,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	435,000	156,000
Actual return on plan assets:
Fair value at end of year	435,000	156,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	27,224,000	24,078,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	27,224,000	24,078,000
Actual return on plan assets:
Fair value at end of year	27,224,000	24,078,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Long Duration Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	48,049,000	34,041,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	48,049,000	34,041,000
Actual return on plan assets:
Fair value at end of year	48,049,000	34,041,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	49,816,000	42,701,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	49,816,000	42,701,000
Actual return on plan assets:
Fair value at end of year	49,816,000	42,701,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | High Yield Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Common trust fund - Bank loans [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	16,187,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	16,187,000
Actual return on plan assets:
Fair value at end of year	16,187,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,035,000	1,098,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,035,000	1,098,000
Actual return on plan assets:
Fair value at end of year	1,035,000	1,098,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Derivatives [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	(49,000)	(17,000)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	(49,000)	(17,000)
Actual return on plan assets:
Fair value at end of year	(49,000)	(17,000)
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Common Trust Fund International Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		24,460,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year		24,460,000
Actual return on plan assets:
Fair value at end of year		24,460,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Common Trust Fund International Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	22,877,000	27,270,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	22,877,000	27,270,000
Actual return on plan assets:
Fair value at end of year	22,877,000	27,270,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Hedge Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	19,829,000	18,571,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	19,829,000	18,571,000
Actual return on plan assets:
Fair value at end of year	19,829,000	18,571,000
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Private Equity Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 2 [Member] | Commodities Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	10,134,000	10,765,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	10,134,000	10,765,000
Actual return on plan assets:
Fair value at end of year	10,134,000	10,765,000
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	2.00%	2.00%
Defined Benefit Plan, Fair Value of Plan Assets	7,158,000	4,659,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	7,158,000	4,659,000
Actual return on plan assets:
Fair value at end of year	7,158,000	4,659,000
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Long Duration Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | High Yield Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Common trust fund - Bank loans [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0
Actual return on plan assets:
Fair value at end of year	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Derivatives [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Common Trust Fund International Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year		0
Actual return on plan assets:
Fair value at end of year		0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Common Trust Fund International Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Hedge Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Private Equity Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	7,158,000	4,659,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	4,659,000	3,522,000
Fair value at end of year	7,158,000	4,659,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	4,659,000	3,522,000
Actual return on plan assets:
Relating to assets still held at the reporting date	1,031,000	116,000
Relating to assets sold during the period	113,000	61,000
Purchases, sales and settlements (net)	1,355,000	960,000
Transfer in/out of Level 3	0	0
Fair value at end of year	7,158,000	4,659,000
Qualified Pension [Member] | Fair Value, Inputs, Level 3 [Member] | Commodities Fund of Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Supplemental Executive Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, General Information	We have pension liabilities related to supplemental executive retirement plans (SERPs) for certain former employees, non-employee directors or surviving spouses. There are no assets related to these SERPs, and no additional benefits accrue to the participants. Payments to the participants are made from operating funds during the year.
Defined Benefit Plan, Information about Plan Assets [Abstract]
Assets for Participant Benefits	0
Officers and Director-Level Employees Life Insurance [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, General Information	We also provide a term life insurance benefit equal to $200,000 to all officers and director-level employees for which we bear the cost of the policies.
Defined Benefit Plan, Information about Plan Assets [Abstract]
Term Life Insurance Per Individual Benefit Provided By Employer	200,000
Term Life Insurance Premiums Paid By Employer	32,000	28,000	25,000
Certain Officers Vice President And Above Life Insurance [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, General Information	We provide term life insurance policies for certain officers at the vice president level and above who were former participants in a terminated SERP; the level of the insurance benefit is dependent upon the level of the benefit provided under the terminated SERP. These life insurance policies are owned exclusively by each officer. Premiums on these policies are paid and expensed.
Defined Benefit Plan, Information about Plan Assets [Abstract]
Term Life Insurance Premiums Paid By Employer	30,000	27,000	43,000
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plans, General Information	We provide certain postretirement health care and life insurance benefits to eligible retirees. The liability associated with such benefits is funded in irrevocable trust funds that can only be used to pay the benefits. Employees are first eligible to retire and receive these benefits at age 55 with ten or more years of service after the age of 45. Employees who met this requirement in 1993 or who retired prior to 1993 are in a “grandfathered” group for whom we pay the full cost of the retiree’s coverage. Retirees not in the grandfathered group have a portion of the cost of retiree coverage paid by us, subject to certain annual contribution limits. Retirees are responsible for the full cost of dependent coverage. Effective January 1, 2008, new employees have to complete ten years of service after age 50 to be eligible for benefits, and no benefits are provided to those employees after age 65 when they are automatically eligible for Medicare benefits to cover health costs. Our OPEB plan includes a defined dollar benefit to pay the premiums for Medicare Part D. Employees who meet the eligibility requirements to retire also receive a life insurance benefit. For employees who retire after July 1, 2005, this benefit is $15,000. The life insurance amount for employees who retired prior to this date was calculated as a percentage of their basic life insurance prior to retirement.
Standard Eligibility Age for Defined Benefit Plan Pre Amendment	55 years
Standard Eligibility Age for Defined Benefit Plan Post Amendment	50 years
Age Of Exclusion For Defined Benefit Plan	65 years
Years After Qualifying Age	10 years
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Defined Benefit Plan, Fair Value of Plan Assets	27,747,000	25,961,000	23,663,000
Benefits Provided After Employee Is Eligible for Medicare Benefits	0
Term Life Insurance Per Individual Benefit Provided By Employer	15,000
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	1,500,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	33,678,000	34,830,000
Service cost	1,109,000	1,327,000	1,387,000
Interest cost	1,448,000	1,130,000	1,347,000
Plan amendments	0	0
Actuarial (gain) loss	3,734,000	(1,094,000)
Participant contributions	805,000	641,000
Administrative expenses	0	0
Benefit payments	(2,957,000)	(3,156,000)
Obligation at end of year	37,817,000	33,678,000	34,830,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	25,961,000	23,663,000
Actual return on plan assets	1,874,000	2,848,000
Employer contributions	2,064,000	1,965,000
Participant contributions	805,000	641,000
Administrative expenses	0	0
Benefit payments	(2,957,000)	(3,156,000)
Fair value at end of year	27,747,000	25,961,000	23,663,000
Funded status at year end - (under) over	(10,070,000)	(7,717,000)
Noncurrent assets	0	0
Current liabilities	0	0
Noncurrent liabilities	(10,070,000)	(7,717,000)
Net amount recognized	(10,070,000)	(7,717,000)
Amounts Not Yet Recognized as a Component of Cost and Recognized in a Deferred Regulatory Account
Unrecognized transition obligation	0	0
Unrecognized prior service (cost) credit	0	0
Unrecognized actuarial loss	(3,995,000)	(354,000)
Regulatory asset	(3,995,000)	(354,000)
Cumulative employer contributions in excess of cost	(6,075,000)	(7,363,000)
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1,109,000	1,327,000	1,387,000
Interest cost	1,448,000	1,130,000	1,347,000
Expected return on plan assets	(1,782,000)	(1,663,000)	(1,551,000)
Transition obligation	0	667,000	667,000
Amortization of prior service cost (credit)	0	0	0
Amortization of net loss	0	0	0
Net periodic benefit cost	775,000	1,461,000	1,850,000
Estimated Amortization And Expected Refunds [Abstract]
Amortization of unrecognized prior service cost (credit)	0
Amortization of unrecognized actuarial loss	29,000
Other Changes In Plan Assets And Benefit Obligatin Recognized Through Regulatory Asset Or Liability [Abstract]
Prior service cost	0	0	0
Net loss (gain)	3,641,000	(2,278,000)	2,209,000
Amounts Recognized As Component Of Net Periodic Benefit Cost [Abstract]
Transition obligation	0	(667,000)	(667,000)
Amortization of net loss	0	0	0
Amortization of prior service (cost) credit	0	0	0
Total recognized in regulatory asset (liability)	3,641,000	(2,945,000)	1,542,000
Total Recognized In Net Periodic Benefit Cost And Regulatory Asset (Liability)	4,416,000	(1,484,000)	3,392,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate	4.03%	4.44%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount Rate	4.44%	3.34%	4.36%
Expected Long Term Rate Of Return On Plan Assets	7.75%	8.00%	8.00%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2015	2,409,000
2016	2,449,000
2017	2,527,000
2018	2,606,000
2019	2,682,000
2020 - 2024	14,179,000
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	7.40%	7.40%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2027	2027
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect of One Percentage Point Increase on Service and Interest Cost Components	31,000
Effect of One Percentage Point Decrease on Service and Interest Cost Components	(32,000)
Effect Of One Percentage Point Increase on Postretirement Benefit Obligation	829,000
Effect of One Percentage Point Decrease on Postretirement Benefit Obligation	(841,000)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	25,961,000	23,663,000
Actual return on plan assets:
Fair value at end of year	27,747,000	25,961,000	23,663,000
Other Postretirement Benefit Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Standard Eligibility Age for Defined Benefit Plan Pre Amendment	45 years
Other Postretirement Benefit Plan [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	3.00%
Defined Benefit Plan, Actual Plan Asset Allocations	9.00%	4.00%
Defined Benefit Plan, Fair Value of Plan Assets	2,590,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	982,000
Fair value at end of year	2,590,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	982,000
Actual return on plan assets:
Fair value at end of year	2,590,000
Other Postretirement Benefit Plan [Member] | Fixed Income Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	45.00%
Defined Benefit Plan, Actual Plan Asset Allocations	44.00%	46.00%
Other Postretirement Benefit Plan [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	7.00%	10.00%
Defined Benefit Plan, Fair Value of Plan Assets	2,013,000	2,582,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	2,013,000	2,582,000
Actual return on plan assets:
Fair value at end of year	2,013,000	2,582,000
Other Postretirement Benefit Plan [Member] | Corporate Bonds Other Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	5.00%
Defined Benefit Plan, Actual Plan Asset Allocations	37.00%	36.00%
Defined Benefit Plan, Fair Value of Plan Assets	10,187,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	9,232,000
Fair value at end of year	10,187,000
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Investment Maturity Date	within ten years
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	9,232,000
Actual return on plan assets:
Fair value at end of year	10,187,000
Other Postretirement Benefit Plan [Member] | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	47.00%
Defined Benefit Plan, Actual Plan Asset Allocations	42.00%	45.00%
Other Postretirement Benefit Plan [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	9.00%	9.00%
Defined Benefit Plan, Fair Value of Plan Assets	2,532,000	2,384,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	2,532,000	2,384,000
Actual return on plan assets:
Fair value at end of year	2,532,000	2,384,000
Other Postretirement Benefit Plan [Member] | International Blend [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	14.00%	16.00%
Defined Benefit Plan, Fair Value of Plan Assets	3,846,000	4,206,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	3,846,000	4,206,000
Actual return on plan assets:
Fair value at end of year	3,846,000	4,206,000
Other Postretirement Benefit Plan [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	4.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	1,269,000	1,327,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,269,000	1,327,000
Actual return on plan assets:
Fair value at end of year	1,269,000	1,327,000
Other Postretirement Benefit Plan [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	1,310,000	1,352,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,310,000	1,352,000
Actual return on plan assets:
Fair value at end of year	1,310,000	1,352,000
Other Postretirement Benefit Plan [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	1,336,000	1,331,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,336,000	1,331,000
Actual return on plan assets:
Fair value at end of year	1,336,000	1,331,000
Other Postretirement Benefit Plan [Member] | Small Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	1,319,000	1,313,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,319,000	1,313,000
Actual return on plan assets:
Fair value at end of year	1,319,000	1,313,000
Other Postretirement Benefit Plan [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Target Plan Asset Allocations	5.00%
Defined Benefit Plan, Actual Plan Asset Allocations	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets	1,345,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	1,252,000
Fair value at end of year	1,345,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	1,252,000
Actual return on plan assets:
Fair value at end of year	1,345,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Defined Benefit Plan, Fair Value of Plan Assets	27,747,000	25,961,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	27,747,000	25,961,000
Actual return on plan assets:
Fair value at end of year	27,747,000	25,961,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	2,590,000	982,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	2,590,000	982,000
Actual return on plan assets:
Fair value at end of year	2,590,000	982,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	2,013,000	2,582,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	2,013,000	2,582,000
Actual return on plan assets:
Fair value at end of year	2,013,000	2,582,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds Other Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	10,187,000	9,232,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	10,187,000	9,232,000
Actual return on plan assets:
Fair value at end of year	10,187,000	9,232,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	2,532,000	2,384,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	2,532,000	2,384,000
Actual return on plan assets:
Fair value at end of year	2,532,000	2,384,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | International Blend [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	3,846,000	4,206,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	3,846,000	4,206,000
Actual return on plan assets:
Fair value at end of year	3,846,000	4,206,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,269,000	1,327,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,269,000	1,327,000
Actual return on plan assets:
Fair value at end of year	1,269,000	1,327,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,310,000	1,352,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,310,000	1,352,000
Actual return on plan assets:
Fair value at end of year	1,310,000	1,352,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,336,000	1,331,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,336,000	1,331,000
Actual return on plan assets:
Fair value at end of year	1,336,000	1,331,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Small Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,319,000	1,313,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,319,000	1,313,000
Actual return on plan assets:
Fair value at end of year	1,319,000	1,313,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,345,000	1,252,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	1,345,000	1,252,000
Actual return on plan assets:
Fair value at end of year	1,345,000	1,252,000
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	0.00%	0.00%
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds Other Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | International Blend [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Small Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Actual Plan Asset Allocations	0.00%	0.00%
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasuries [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds Other Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Large Cap Index [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | International Blend [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Large Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Large Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Small Cap Value [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Small Cap Growth [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Global REIT [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at end of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0
NCNG SERP [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate	3.64%
Directors SERP [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate	3.74%
Piedmont SERP [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate	3.10%
Non Qualified Pension [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0	0
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	521,000
Reconciliation Of Changes In Plan Benefit Obligations And Fair Value Of Assets [Abstract]
Accumulated Benefit Obligation At Year End	5,925,000	4,736,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	4,736,000	5,569,000
Service cost	0	0	39,000
Interest cost	200,000	157,000	203,000
Plan amendments	485,000	0
Actuarial (gain) loss	956,000	(540,000)
Participant contributions	0	0
Administrative expenses	0	0
Benefit payments	(452,000)	(450,000)
Obligation at end of year	5,925,000	4,736,000	5,569,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	452,000	450,000
Participant contributions	0	0
Administrative expenses	0	0
Benefit payments	(452,000)	(450,000)
Fair value at end of year	0	0	0
Funded status at year end - (under) over	(5,925,000)	(4,736,000)
Noncurrent assets	0	0
Current liabilities	(521,000)	(445,000)
Noncurrent liabilities	(5,404,000)	(4,291,000)
Net amount recognized	(5,925,000)	(4,736,000)
Amounts Not Yet Recognized as a Component of Cost and Recognized in a Deferred Regulatory Account
Unrecognized transition obligation	0	0
Unrecognized prior service (cost) credit	(439,000)	(196,000)
Unrecognized actuarial loss	(1,745,000)	(820,000)
Regulatory asset	(2,184,000)	(1,016,000)
Cumulative employer contributions in excess of cost	(3,741,000)	(3,720,000)
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0	0	39,000
Interest cost	200,000	157,000	203,000
Expected return on plan assets	0	0	0
Transition obligation	0	0	0
Amortization of prior service cost (credit)	243,000	81,000	81,000
Amortization of net loss	31,000	161,000	49,000
Net periodic benefit cost	474,000	399,000	372,000
Estimated Amortization And Expected Refunds [Abstract]
Amortization of unrecognized prior service cost (credit)	231,000
Amortization of unrecognized actuarial loss	85,000
Other Changes In Plan Assets And Benefit Obligatin Recognized Through Regulatory Asset Or Liability [Abstract]
Prior service cost	485,000	0	0
Net loss (gain)	956,000	(540,000)	629,000
Amounts Recognized As Component Of Net Periodic Benefit Cost [Abstract]
Transition obligation	0	0	0
Amortization of net loss	(31,000)	(161,000)	(49,000)
Amortization of prior service (cost) credit	(243,000)	(81,000)	(81,000)
Total recognized in regulatory asset (liability)	1,167,000	(782,000)	499,000
Total Recognized In Net Periodic Benefit Cost And Regulatory Asset (Liability)	1,641,000	(383,000)	871,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate	3.69%	3.98%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount Rate	3.98%	2.95%	4.10%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2015	521,000
2016	507,000
2017	491,000
2018	472,000
2019	490,000
2020 - 2024	2,149,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of year	0	0
Actual return on plan assets:
Fair value at end of year	0	0	0
Other Postretirement Benefit Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Current Liability	214,000	199,000
Noncurrent Liability	4,248,000	3,328,000
Money Purchase Pension Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Description of Defined Contribution Pension and Other Postretirement Plans	Employees hired or rehired after December 31, 2007 cannot participate in the qualified pension plan but are participants in the Money Purchase Pension (MPP) plan, a defined contribution pension plan that allows the employee to direct the investments and assume the risk of investment returns. A defined contribution plan specifies the amount of the employer’s annual contribution to individual participant accounts established for the retirement benefit. Eligible employees who have completed 30 days of continuous service and have attained age 18 are eligible to participate. Under the MPP plan, we annually deposit a percentage of each participant’s pay into an account of the MPP plan. This contribution equals 4% of the participant’s compensation plus an additional 4% of compensation above the social security wage base up to the Internal Revenue Service (IRS) compensation limit. The participant is vested in this plan after three years of service.
Defined Contribution Plans Estimated Future Employer Contributions In Next Fiscal Year	1,300,000
Money Purchase Pension Plan [Member] | Pension Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Service Required For Eligibility In Defined Contribution Plan	30 days
Standard Eligibility Age For Defined Contribution Plan	18 years
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Employer Contribution Percentage Above IRS Limit	4.00%
Employer Contribution to Plan	900,000
Plan Vesting Period Defined Contribution Plan	3 years
Voluntary Deferral Plan [Member] | Other Postretirement Benefit Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer Contribution to Plan	0
Deferral Limit As Percentage Of Base Salary	50.00%
Plan Deferral Limit As Percentage Of Annual Incentive Pay	95.00%
Distribution Deferral Time Period Minimum In Years	2 years
Defined Contribution Restoration Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Description of Defined Contribution Pension and Other Postretirement Plans	We have a non-qualified defined contribution restoration plan (DCR plan) for all officers at the vice president level and above where benefits payable under the plan are informally funded annually through a rabbi trust with a bank as the trustee. We contribute 13% of the total cash compensation (base salary, short-term incentive and MVP incentive) that exceeds the IRS compensation limit to the DCR plan account of each covered executive. Participants may not contribute to the DCR plan. Vesting under the DCR plan is five-year cliff vesting, including service prior to adoption of the plan on January 1, 2009, of annual company contributions, and prospective five-year cliff vesting for the one-time opening balances of four Vice Presidents to compensate them for the loss of future benefits under this DCR plan as compared with a terminated SERP. Participants in the DCR plan may provide instructions to us for the deemed investment of their plan accounts. Distribution will occur upon separation of service or death of the participant.
Defined Contribution Restoration Plan [Member] | Other Postretirement Benefit Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer Contribution Percentage Above IRS Limit	13.00%
Employer Contribution to Plan	524,000	434,000
Plan Vesting Period Defined Contribution Plan	5 years
Vice Presidents Eligible For One Time Contribution New DCR Plan	4
Plan 401 K [Member]
Defined Contribution Plan Disclosure [Line Items]
Description of Defined Contribution Pension and Other Postretirement Plans	We maintain a 401(k) plan that is a profit-sharing plan under Section 401(a) of the Internal Revenue Code of 1986, as amended (the Tax Code), which includes qualified cash or deferred arrangements under Tax Code Section 401(k). The 401(k) plan is subject to the provisions of the Employee Retirement Income Security Act. Eligible employees who have completed 30 days of continuous service and have attained age 18 are eligible to participate. Participants may defer a portion of their base salary and cash incentive payments to the plan, and we match a portion of their contributions. Employee contributions vest immediately, and company contributions vest after six months of service. Employees receive a company match of 100% up to the first 5% of eligible pay contributed. Employees may contribute up to 50% of eligible pay to the 401(k) on a pre-tax basis, up to the Tax Code annual contribution and compensation limits. We automatically enroll all eligible non-participating employees in the 401(k) plan at a 2% contribution rate unless the employee chooses not to participate by notifying our record keeper. For employees who are automatically enrolled in the 401(k) plan, we automatically increase their contributions by 1% each year to a maximum of 5% unless the employee chooses to opt out of the automatic increase by contacting our record keeper. If the employee does not make an investment election, employee contributions and matches are automatically invested in a diversified portfolio of stocks and bonds. Participants may direct up to 20% of their contributions and company matching contributions as an investment in the Piedmont Stock Fund. Employees may change their contribution rate and investments at any time.
Plan 401 K [Member] | Other Postretirement Benefit Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Service Required For Eligibility In Defined Contribution Plan	30 days
Standard Eligibility Age For Defined Contribution Plan	18 years
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	5.00%
Employer Contribution to Plan	$ 6,134,000	$ 5,688,000	$ 5,400,000
Plan Vesting Period Defined Contribution Plan	6 months
Employer Match Percentage	100.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	50.00%
Employee Contribution Rate At Enrollment	2.00%
Contribution Annual Automatic Deferral Increase	1.00%
Employee Contribution Automatic Increase Rate Cap	5.00%
Investment In Company Stock Cap	20.00%