Consolidated Statements of Operations and Comprehensive Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Noninterest Expense:
Impairment loss on investment securities, other than-temporary loss	$ 3,700,000	$ 1,500,000
Other comprehensive (loss) income, net of tax
Unrealized gain (loss) on available for sale securities, tax	(44,000)	237,000
Other comprehensive income (loss), pension and other postretirement benefit plans, tax	$ 8,000