Stockholders' Equity (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Changes in other comprehensive income (loss)
Balance at the beginning of the period	$ (16,211)	$ (43,173)	$ (15,859)	$ (46,797)
Other comprehensive income before reclassification	3,570	(158)	4,051	5,055
Amount reclassified from accumulated other comprehensive income	(1,115)	(2,653)	(1,948)	(4,242)
Net current period other comprehensive income (loss)	2,455	(2,811)	2,103	813
Balance at the end of the period	(13,756)	(45,984)	(13,756)	(45,984)
Unrealized gains on investment securities
Changes in other comprehensive income (loss)
Balance at the beginning of the period	2,709	3,567	3,150	1,823
Other comprehensive income before reclassification	2,253	(89)	2,557	3,190
Amount reclassified from accumulated other comprehensive income	(884)	(2,047)	(1,629)	(3,582)
Net current period other comprehensive income (loss)	1,369	(2,136)	928	(392)
Balance at the end of the period	4,078	1,431	4,078	1,431
Change in valuation allowance for unrealized gains (losses) on investment securities
Changes in other comprehensive income (loss)
Balance at the beginning of the period	552	1,066	810	32
Other comprehensive income before reclassification	1,317	(69)	1,494	1,865
Amount reclassified from accumulated other comprehensive income	(516)	(1,198)	(951)	(2,098)
Net current period other comprehensive income (loss)	801	(1,267)	543	(233)
Balance at the end of the period	1,353	(201)	1,353	(201)
Pension and postretirement benefits
Changes in other comprehensive income (loss)
Balance at the beginning of the period	(19,472)	(47,806)	(19,819)	(48,652)
Amount reclassified from accumulated other comprehensive income	285	592	632	1,438
Net current period other comprehensive income (loss)	285	592	632	1,438
Balance at the end of the period	$ (19,187)	$ (47,214)	$ (19,187)	$ (47,214)