Stockholder's Equity (Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax charge on comprehensive income	$ (94)	$ 779
Retirement plans | Reclassifications out of other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of loss and settlement loss	247	1,021
Income tax charge on comprehensive income	(94)	(388)
Total	$ 153	$ 633