Stockholders' Equity (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	$ (47,690)	$ (16,211)	$ (50,443)	$ (15,859)
Other comprehensive income before reclassification	(4,516)	3,570	(380)	4,051
Amount reclassified from accumulated other comprehensive income	475	(1,115)	(908)	(1,948)
Net current period other comprehensive income (loss)	(4,041)	2,455	(1,288)	2,103
Balance at the end of the period	(51,731)	(13,756)	(51,731)	(13,756)
Unrealized gains on investment securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	421	2,709	(727)	3,150
Other comprehensive income before reclassification	(2,845)	2,253	(222)	2,557
Amount reclassified from accumulated other comprehensive income	(289)	(884)	(1,764)	(1,629)
Net current period other comprehensive income (loss)	(3,134)	1,369	(1,986)	928
Balance at the end of the period	(2,713)	4,078	(2,713)	4,078
Change in valuation allowance for unrealized gains (losses) on investment securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	(809)	552	(1,471)	810
Other comprehensive income before reclassification	(1,671)	1,317	(158)	1,494
Amount reclassified from accumulated other comprehensive income	(169)	(516)	(1,020)	(951)
Net current period other comprehensive income (loss)	(1,840)	801	(1,178)	543
Balance at the end of the period	(2,649)	1,353	(2,649)	1,353
Pension and postretirement benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at the beginning of the period	(47,302)	(19,472)	(48,245)	(19,819)
Amount reclassified from accumulated other comprehensive income	933	285	1,876	632
Net current period other comprehensive income (loss)	933	285	1,876	632
Balance at the end of the period	$ (46,369)	$ (19,187)	$ (46,369)	$ (19,187)