Fair Value of Assets and Liabilities (Details 1) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2011
Reconciliation of opening and closing balances for assets measured at fair value on recurring basis
Balance as of December 31, 2010	$ 6,751
Total unrealized gains (losses) for the period included in other comprehensive income	2,011
Amortization, accretion and principal payments	(2,240)
Balance as of September 30, 2011	6,522
Collateralized debt obligations [Member]
Reconciliation of opening and closing balances for assets measured at fair value on recurring basis
Balance as of December 31, 2010	6,595
Total unrealized gains (losses) for the period included in other comprehensive income	2,095
Amortization, accretion and principal payments	(2,240)
Balance as of September 30, 2011	6,450
Residential mortgage-backed securities [Member]
Reconciliation of opening and closing balances for assets measured at fair value on recurring basis
Balance as of December 31, 2010	156
Total unrealized gains (losses) for the period included in other comprehensive income	(84)
Balance as of September 30, 2011	$ 72