Investment Securities Schedule of Amortized Cost and Fair Values of Investment Securities (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Statement [Line Items]
Held-to-maturity Securities	$ 6,734	$ 7,751
Held-to-maturity Securities, Unrecognized Holding Gain	47	68
Held-to-maturity Securities, Unrecognized Holding Loss	(7)	(1)
Held-to-maturity Securities, Fair Value	6,774	7,818
Available-for-sale Securities, Amortized Cost Basis	2,716,977	2,822,965
Available-for-sale Securities, Gross Unrealized Gains	86,642	69,284
Available-for-sale Securities, Gross Unrealized Losses	(33,796)	(38,516)
Available-for-sale Securities	2,769,823	2,853,733
U.S. Government-Sponsored Agency Securities [Member]
Statement [Line Items]
Held-to-maturity Securities	5,987	6,339
Held-to-maturity Securities, Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Unrecognized Holding Loss	(7)	(1)
Held-to-maturity Securities, Fair Value	5,980	6,338
U.S. Government-Sponsored Agency Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	4,735	4,888
Available-for-sale Securities, Gross Unrealized Gains	110	172
Available-for-sale Securities, Gross Unrealized Losses	(1)	(2)
Available-for-sale Securities	4,844	5,058
State and Municipal Securities [Member]
Statement [Line Items]
Held-to-maturity Securities	179	346
Held-to-maturity Securities, Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	179	346
State and Municipal Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	320,969	345,053
Available-for-sale Securities, Gross Unrealized Gains	13,091	6,003
Available-for-sale Securities, Gross Unrealized Losses	0	(1,493)
Available-for-sale Securities	334,060	349,563
Mortgage-Backed Securities [Member]
Statement [Line Items]
Held-to-maturity Securities	568	1,066
Held-to-maturity Securities, Unrecognized Holding Gain	47	68
Held-to-maturity Securities, Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	615	1,134
Mortgage-Backed Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	802,142	843,446
Available-for-sale Securities, Gross Unrealized Gains	36,763	31,080
Available-for-sale Securities, Gross Unrealized Losses	(69)	(3,054)
Available-for-sale Securities	838,836	871,472
Equity Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	123,483	133,570
Available-for-sale Securities, Gross Unrealized Gains	2,291	3,872
Available-for-sale Securities, Gross Unrealized Losses	(5,408)	(974)
Available-for-sale Securities	120,366	136,468
U.S. Government Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,325	1,649
Available-for-sale Securities, Gross Unrealized Gains	0	0
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities	1,325	1,649
Corporate Debt Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	130,455	137,101
Available-for-sale Securities, Gross Unrealized Gains	4,892	3,808
Available-for-sale Securities, Gross Unrealized Losses	(12,912)	(16,123)
Available-for-sale Securities	122,435	124,786
Collateralized Mortgage Obligations [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,078,396	1,085,613
Available-for-sale Securities, Gross Unrealized Gains	29,212	23,457
Available-for-sale Securities, Gross Unrealized Losses	(353)	(5,012)
Available-for-sale Securities	1,107,255	1,104,058
Auction Rate Securities [Member]
Statement [Line Items]
Available-for-sale Securities, Amortized Cost Basis	255,472	271,645
Available-for-sale Securities, Gross Unrealized Gains	283	892
Available-for-sale Securities, Gross Unrealized Losses	(15,053)	(11,858)
Available-for-sale Securities	$ 240,702	$ 260,679

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

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+ Details