Fair Value Measurements (Details 3) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Total realized/unrealized gains (losses):
Paydowns received on Level 3 assets measured on a recurring basis	$ 3,200,000	$ 2,000,000
Securities Available-for-Sale
Level 3 Assets Measured on a Recurring Basis
Balance, beginning of period	19,583,000	20,982,000
Total realized/unrealized gains (losses):
Included in other comprehensive income	1,770,000	348,000
Settlements	(3,152,000)	(1,960,000)
Transfers into level 3	47,165,000
Other (1)	73,000	(20,000)
Balance, end of period	$ 65,439,000	$ 19,350,000