For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6503844

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (e)

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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-SubTopic 20

-Section 50

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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

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Employee Benefit Plans (Fair Value of the Company’s Qualified Pension Plan Assets by Category) (Details) (Pension plans, USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	$ 48,656,000	$ 49,873,000	$ 46,547,000
Accumulated benefit obligation	48,200,000	45,600,000
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	6,356,000	27,049,000
Actual plan asset allocations (as a percentage)		11.10%
Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	41,351,000	18,990,000
Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	949,000	3,834,000
Equity Securities, Large Company
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		52.80%
Equity Securities, Small Company
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		11.10%
Equity Securities, Medium Company
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		12.10%
Equity Securities, Foreign Company
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		17.20%
Equity Securities, Other Companies
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		6.80%
Equity Securities, Mutual Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		88.90%
Exchange Traded Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual plan asset allocations (as a percentage)		33.40%
Quoted prices in active markets for identical assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	949,000	49,873,000
Quoted prices in active markets for identical assets (Level 1) \| Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	0	27,049,000
Quoted prices in active markets for identical assets (Level 1) \| Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	0	18,990,000
Quoted prices in active markets for identical assets (Level 1) \| Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	949,000	3,834,000
Significant observable inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	47,707,000	0
Significant observable inputs (Level 2) \| Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	6,356,000	0
Significant observable inputs (Level 2) \| Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	41,351,000	0
Significant observable inputs (Level 2) \| Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	0	0
Significant unobservable inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	0	0
Significant unobservable inputs (Level 3) \| Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	0	0
Significant unobservable inputs (Level 3) \| Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	0	0
Significant unobservable inputs (Level 3) \| Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair value of qualified plan assets	$ 0	$ 0