Investment in Securities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Held-to-maturity securities:
Amortized Cost Basis	$ 75,061	$ 89,391
Gross Unrealized Gains	2,017	1,827
Gross Unrealized Losses	1	122
Fair Value	77,077	91,096
U.S. government sponsored enterprise mortgage-backed securities [Member]
Held-to-maturity securities:
Amortized Cost Basis	50,939	46,432
Gross Unrealized Gains	1,576	1,168
Gross Unrealized Losses		97
Fair Value	52,515	47,503
U.S. government and federal agency obligations [Member]
Held-to-maturity securities:
Amortized Cost Basis		5,600
Gross Unrealized Gains		59
Fair Value		5,659
Corporate debt securities [Member]
Held-to-maturity securities:
Amortized Cost Basis	24,122	37,359
Gross Unrealized Gains	441	600
Gross Unrealized Losses	1	25
Fair Value	$ 24,562	$ 37,934