Benefit Plans - Balances of Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Prior service cost	$ 15	$ 34
Net actuarial loss	(22,855)	(8,579)
Total	(22,870)	(8,613)
Deferred taxes	(8,005)	(3,015)
Accumulated other comprehensive loss	$ (14,865)	$ (5,598)

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from other provisions, reserves, allowances, and accruals not separately disclosed.

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

-Publisher FASB

-Name Accounting Standards Codification

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-Glossary Deferred Tax Asset

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The pretax total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

+ References

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- Definition

Amount after tax of cost (credit) of benefit changes attributable to plan participants' prior service resulting from a plan amendment or plan initiation that has not been recognized in net periodic benefit cost (credit).

+ References

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Amount after tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit.

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- Definition

Amount before tax of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) related to pension and other postretirement benefit plans.

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