Stockholder's Equity (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax credit (charge) on comprehensive income	$ (1,571)	$ (17)	$ (792)	$ 100
Retirement plans | Reclassifications out of accumulated other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of (gain) loss and settlement loss	1,585	44	2,529	(245)
Income tax credit (charge) on comprehensive income	(602)	(17)	(961)	100
Net of tax	$ 983	$ 27	$ 1,568	$ (145)