Employee Benefit Plans (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Pension Benefits
Details of the pre-tax amounts recognized in accumulated other comprehensive loss
Balance at beginning of year, Unamortized Actuarial Net Losses	$ 37,536
Balance at beginning of year, Unamortized Prior Service Costs	0
Amounts arising during the period, Unamortized Actuarial Net Losses	27,986
Amounts arising during the period, Unamortized Prior Service Costs	0
Amounts recognized as a component of net periodic benefit cost, Unamortized Actuarial Net Losses	(934)
Amounts recognized as a component of net periodic benefit cost, Unamortized Prior Service Costs	0
Balance at end of year, Unamortized Actuarial Net Losses	64,588
Balance at end of year, Unamortized Prior Service Costs	0
Postretirement Benefits
Details of the pre-tax amounts recognized in accumulated other comprehensive loss
Balance at beginning of year, Unamortized Actuarial Net Losses	11,738
Balance at beginning of year, Unamortized Prior Service Costs	(1,441)
Amounts arising during the period, Unamortized Actuarial Net Losses	7,341
Amounts arising during the period, Unamortized Prior Service Costs	0
Amounts recognized as a component of net periodic benefit cost, Unamortized Actuarial Net Losses	(812)
Amounts recognized as a component of net periodic benefit cost, Unamortized Prior Service Costs	543
Balance at end of year, Unamortized Actuarial Net Losses	18,267
Balance at end of year, Unamortized Prior Service Costs	$ (898)