Note 11 - Fair Value Measurements (Detail) - Assets and Liabilities Measured at Fair Value on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Securities available-for-sale
Securities Available-for-Sale	$ 1,293,571	$ 1,294,478
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	309,920
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	0
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0
US Treasury Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	309,920
US Treasury Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	309,920
U.S. Government Sponsored Entities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
U.S. Government Sponsored Entities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	50,103	501,226
U.S. Government Sponsored Entities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
U.S. Government Sponsored Entities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	50,103	501,226
U.S. Government Sponsored Entities [Member]
Securities available-for-sale
Securities Available-for-Sale	50,103	501,226
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	566,751	337,631
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Collateralized Mortgage Backed Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	566,751	337,631
Collateralized Mortgage Backed Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	566,751	337,631
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	11,781	16,486
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Collateralized Mortgage Obligations [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	11,781	16,486
Collateralized Mortgage Obligations [Member]
Securities available-for-sale
Securities Available-for-Sale	11,781	16,486
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	146	166
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Asset-backed Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	146	166
Asset-backed Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	146	166
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	337,549	380,429
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Corporate Debt Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	337,549	380,429
Corporate Debt Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	337,549	380,429
Mutual Funds Member | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	6,149	6,035
Mutual Funds Member | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Mutual Funds Member | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Mutual Funds Member | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	6,149	6,035
Mutual Funds Member
Securities available-for-sale
Securities Available-for-Sale	6,149	6,035
Preferred Stock Of Government Sponsored Entities Member | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Preferred Stock Of Government Sponsored Entities Member | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	887	1,654
Preferred Stock Of Government Sponsored Entities Member | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Preferred Stock Of Government Sponsored Entities Member | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	887	1,654
Preferred Stock Of Government Sponsored Entities Member
Securities available-for-sale
Securities Available-for-Sale	887	1,654
Trust Preferred Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Trust Preferred Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	10,285	45,963
Trust Preferred Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Trust Preferred Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	10,285	45,963
Trust Preferred Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	10,285	45,963
Trading Securities Member | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Total Assets	0	2
Trading Securities Member | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	4,619	4,540
Trading Securities Member | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	0	0
Trading Securities Member | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Total Assets	4,619	4,542
Warrant [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Total Assets	0	0
Warrant [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	0	0
Warrant [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	114	218
Warrant [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Total Assets	114	218
Option Contracts Member | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Total Assets	0	0
Liabilities
Total Liabilities	0	0
Option Contracts Member | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	56	34
Liabilities
Total Liabilities	49	5
Option Contracts Member | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	0	0
Liabilities
Total Liabilities	0	0
Option Contracts Member | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Total Assets	56	34
Liabilities
Total Liabilities	49	5
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Total Assets	0	0
Liabilities
Total Liabilities	0	0
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	2,401	2,151
Liabilities
Total Liabilities	1,018	486
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	0	0
Liabilities
Total Liabilities	0	0
Foreign Exchange Contract [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Total Assets	2,401	2,151
Liabilities
Total Liabilities	1,018	486
State and Municipal Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale		0
State and Municipal Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale		1,928
State and Municipal Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale		0
State and Municipal Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale		1,928
State and Municipal Securities [Member]
Securities available-for-sale
Securities Available-for-Sale		1,928
Other Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale		2,960
Other Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale		0
Other Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale		0
Other Equity Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale		2,960
Other Equity Securities [Member]
Securities available-for-sale
Securities Available-for-Sale		2,960
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Total Liabilities		0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Total Liabilities		2,634
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Total Liabilities		0
Interest Rate Swap [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Liabilities
Total Liabilities		2,634
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	316,069	8,995
Total Assets	316,069	8,997
Liabilities
Total Liabilities	0	0
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	977,502	1,285,483
Total Assets	984,578	1,292,208
Liabilities
Total Liabilities	1,067	3,125
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Total Assets	114	218
Liabilities
Total Liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	1,293,571	1,294,478
Total Assets	1,300,761	1,301,423
Liabilities
Total Liabilities	$ 1,067	$ 3,125