Employee Benefit Plans (Narrative) (Details)	1 Months Ended	12 Months Ended
	Jan. 31, 2016 shares	Dec. 31, 2015 USD ($) item shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Pension plan, underfunded amount		$ 1,400,000
Maximum percentage of equity securities in any single industry (in hundredths)		25.00%
Maximum percentage of fixed income securities by any issuer		10.00%
Maximum percentage of equity securities in any single corporation		10.00%
Health care cost trend rate assumed		6.90%
Dental care cost trend rate assumed		5.00%
Decrease health care cost trend rate in 2016			0.20%
Decrease health care cost trend rate in 2017		0.70%
Decrease health care cost trend rate in 2018		0.60%
Increase health care cost trend rate in 2019		0.10%
Increase health care cost trend rate from 2020-2026		0.40%
Accumulated benefit obligations for pension plan		$ 33,700,000	$ 33,700,000
Minimum age limit for applicability of health and dental care cost trends | item		65
Stock Awards [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares authorized under the plan | shares		400,000
Union Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan		$ 2,500,000	2,700,000
Subsequent Event [Member] | 2011 Stock Incentive Plan Twenty Eleven [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares authorized under the plan | shares	160,759
Shares available to be issued under plan | shares	340,000
Chairman One [Member]
Defined Benefit Plan Disclosure [Line Items]
Liability for future policy benefits of former chairman		822,000	822,000
Chairman Two [Member]
Defined Benefit Plan Disclosure [Line Items]
Liability for future policy benefits of former chairman		627,000
Future policy benefits reserve		526,000	503,000
Independent Director [Member] | Subsequent Event [Member] | 2011 Stock Incentive Plan Twenty Eleven [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares issued under plan | shares	60,000
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of assets		35,118,000	35,772,000	$ 34,414,000
Projected pension obligation		36,503,000	$ 36,735,000	32,897,000
Pension plan, underfunded amount		$ 1,400,000
Discount rate		4.50%	4.00%
Defined Benefit Plan, Funded Status of Plan		$ 1,385,000	$ 963,000
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected pension obligation		9,919,000	$ 12,127,000	$ 12,530,000
Pension plan, underfunded amount		$ 9,900,000
Discount rate		4.50%	4.00%
Defined Benefit Plan, Funded Status of Plan		$ 9,919,000	$ 12,127,000
401(k) [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contribution amount		$ 103,525	111,000
Annual contribution per employee percentage		50.00%
Annual contribution per employee amount		$ 2,000
Accounts Payable and Accrued Liabilities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan, underfunded amount		500,000	600,000
Other Long-term Liabilities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan, underfunded amount		$ 9,400,000	$ 11,500,000
Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocation		70.00%
Actual plan asset allocation		69.70%	71.20%
Fair value of assets		$ 24,500,000	$ 25,500,000
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocation		30.00%
Actual plan asset allocation		30.30%	28.80%
Fair value of assets		$ 10,600,000	$ 10,300,000