Securities (Amortized cost and fair value of securities) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Available-for-sale Securities
Securities available for sale, amortized cost	$ 595,803	$ 607,680
Securities available for sale, gross unrealized gains	10,424	9,554
Securities available for sale, gross unrealized losses	(1,287)	(3,775)
Securities available for sale, fair value	604,940	613,459
Held-to-maturity Securities
Securities held to maturity, amortized cost	191,328	196,635
Securities held to maturity, gross unrealized gains	4,060	3,707
Securities held to maturity, gross unrealized losses	(179)	(485)
Securities held to maturity, fair value	195,209	199,857
Debt Securities [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	127,087
U.S. Government agency securities [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	110,982	97,750
Securities held to maturity, gross unrealized gains	782	88
Securities held to maturity, gross unrealized losses	(29)	0
Securities held to maturity, fair value	111,735	97,838
Residential mortgage-backed securities [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	29,351	37,658
Securities held to maturity, gross unrealized gains	2,301	2,769
Securities held to maturity, gross unrealized losses	0	0
Securities held to maturity, fair value	31,652	40,427
Agency CMOs [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	34,890	45,122
Securities held to maturity, gross unrealized gains	950	840
Securities held to maturity, gross unrealized losses	0	(1)
Securities held to maturity, fair value	35,840	45,961
Corporate debt securities [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	15,000	15,000
Securities held to maturity, gross unrealized gains	0	0
Securities held to maturity, gross unrealized losses	(150)	(484)
Securities held to maturity, fair value	14,850	14,516
Municipal securities [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	1,105	1,105
Securities held to maturity, gross unrealized gains	27	10
Securities held to maturity, gross unrealized losses	0	0
Securities held to maturity, fair value	1,132	1,115
Debt Securities [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	50,614
U.S. Government agency securities [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	10,000	22,500
Securities available for sale, gross unrealized gains	1	58
Securities available for sale, gross unrealized losses	0	0
Securities available for sale, fair value	10,001	22,558
Residential mortgage-backed securities [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	70,356	21,087
Securities available for sale, gross unrealized gains	1,244	325
Securities available for sale, gross unrealized losses	0	0
Securities available for sale, fair value	71,600	21,412
Agency CMOs [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	468,575	519,167
Securities available for sale, gross unrealized gains	9,151	9,171
Securities available for sale, gross unrealized losses	(230)	(175)
Securities available for sale, fair value	477,496	528,163
Private-label CMOs [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	6,258	24,974
Securities available for sale, gross unrealized gains	0	0
Securities available for sale, gross unrealized losses	(254)	(1,968)
Securities available for sale, fair value	6,004	23,006
Held-to-maturity Securities
Securities held to maturity, amortized cost	0
Corporate debt securities [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	19,956	19,952
Securities available for sale, gross unrealized gains	0	0
Securities available for sale, gross unrealized losses	(690)	(1,632)
Securities available for sale, fair value	19,266	18,320
Municipal securities [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	20,658
Securities available for sale, gross unrealized gains	28
Securities available for sale, gross unrealized losses	(113)
Securities available for sale, fair value	$ 20,573

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

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