Stockholders' Equity (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Changes in other comprehensive income (loss)
Balance at the beginning of the period	$ (15,859)	$ (46,797)
Other comprehensive income before reclassification	483	5,213
Amount reclassified from accumulated other comprehensive income	(835)	(1,589)
Net current period other comprehensive income (loss)	(352)	3,624
Balance at the end of the period	(16,211)	(43,173)
Unrealized gains on investment securities
Changes in other comprehensive income (loss)
Balance at the beginning of the period	3,150	1,823
Other comprehensive income before reclassification	307	3,279
Amount reclassified from accumulated other comprehensive income	(748)	(1,535)
Net current period other comprehensive income (loss)	(441)	1,744
Balance at the end of the period	2,709	3,567
Change in valuation allowance for unrealized gains (losses) on investment securities
Changes in other comprehensive income (loss)
Balance at the beginning of the period	810	32
Other comprehensive income before reclassification	176	1,934
Amount reclassified from accumulated other comprehensive income	(434)	(900)
Net current period other comprehensive income (loss)	(258)	1,034
Balance at the end of the period	552	1,066
Pension and postretirement benefits
Changes in other comprehensive income (loss)
Balance at the beginning of the period	(19,819)	(48,652)
Amount reclassified from accumulated other comprehensive income	347	846
Net current period other comprehensive income (loss)	347	846
Balance at the end of the period	$ (19,472)	$ (47,806)