Consolidated Statements of Operations and Comprehensive Income (unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Noninterest Expense:
Impairment loss on investment securities, other than-temporary loss			$ 3,600,000	$ 308,000
Impairment loss on investment securities, other comprehensive loss			1,300,000
Other comprehensive (loss) income, net of tax
Unrealized gain (loss) on available for sale securities and past service costs of employee benefit plans, income tax expense	$ 324,000	$ 14,000	$ 597,000	$ (292,000)