Fair Value of Assets and Liabilities (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Reconciliation of opening and closing balances for assets measured at fair value on recurring basis
Balance at December 31, 2010	$ 6,751
Total unrealized gains (losses) for the period included in other comprehensive income	4,167
Amortization, accretion and principal payments	(5,530)
Transfers out of Level 3	(5,388)
Balance at December 31, 2011	0
Collateralized debt obligations [Member]
Reconciliation of opening and closing balances for assets measured at fair value on recurring basis
Balance at December 31, 2010	6,595
Total unrealized gains (losses) for the period included in other comprehensive income	4,301
Amortization, accretion and principal payments	(5,530)
Transfers out of Level 3	(5,366)
Balance at December 31, 2011	0
Residential mortgage-backed securities [Member]
Reconciliation of opening and closing balances for assets measured at fair value on recurring basis
Balance at December 31, 2010	156
Total unrealized gains (losses) for the period included in other comprehensive income	(134)
Transfers out of Level 3	(22)
Balance at December 31, 2011	$ 0