Note 3 - Securities (Detail) - Remaining Contractual Maturity of Securities (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Available-for-Sale Securities - Fair Value	$ 1,191,582	$ 1,013,006
Held-to-Maturity Securities - Amortized Cost	41,944	60,458
Held-to-Maturity Securities - Fair Value	45,633	61,477
Amortized Cost [Member] \| Collateralized Mortgage Obligation [Member]
Available-for-Sale Securities - Amortized Cost	511,242
Amortized Cost [Member] \| Other Residential Mortgage-Backed Securities [Member]
Available-for-Sale Securities - Amortized Cost	128,750
Amortized Cost [Member] \| Total Equity Securities [Member]
Available-for-Sale Securities - Amortized Cost	9,526
Amortized Cost [Member]
One year or less	10,118
One year to five years	364,520
Five years to ten years	91,830
After ten years	69,637
Available-for-Sale Securities - Amortized Cost	1,185,623
Fair Value [Member] \| Collateralized Mortgage Obligation [Member]
Available-for-Sale Securities - Fair Value	513,432
Fair Value [Member] \| Other Residential Mortgage-Backed Securities [Member]
Available-for-Sale Securities - Fair Value	135,135
Fair Value [Member] \| Total Equity Securities [Member]
Available-for-Sale Securities - Fair Value	10,840
Fair Value [Member]
One year or less	10,044
One year to five years	361,848
Five years to ten years	91,157
After ten years	69,126
Available-for-Sale Securities - Fair Value	1,191,582
Amortized Cost [Member]
One year or less	7,003
One year to five years	10,368
Five years to ten years	8,409
After ten years	16,164
Held-to-Maturity Securities - Amortized Cost	41,944
Fair Value [Member]
One year or less	7,619
One year to five years	11,280
Five years to ten years	9,148
After ten years	17,586
Held-to-Maturity Securities - Fair Value	$ 45,633

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

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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