Stockholders' Equity (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Changes in other comprehensive income (loss)
Balance at the beginning of the period	$ (46,797)
Other comprehensive income before reclassification	5,213
Amount reclassified from accumulated other comprehensive income	(1,589)
Net current period other comprehensive income	3,624
Balance at the end of the period	(43,173)
Unrealized gains on investment securities
Changes in other comprehensive income (loss)
Balance at the beginning of the period	1,823
Other comprehensive income before reclassification	3,279
Amount reclassified from accumulated other comprehensive income	(1,535)
Net current period other comprehensive income	1,744
Balance at the end of the period	3,567
Decrease of valuation allowance for unrealized gains on investment securities
Changes in other comprehensive income (loss)
Balance at the beginning of the period	32
Other comprehensive income before reclassification	1,934
Amount reclassified from accumulated other comprehensive income	(900)
Net current period other comprehensive income	1,034
Balance at the end of the period	1,066
Pension and postretirement benefits
Changes in other comprehensive income (loss)
Balance at the beginning of the period	(48,652)
Amount reclassified from accumulated other comprehensive income	846
Net current period other comprehensive income	846
Balance at the end of the period	$ (47,806)