Note 11 - Fair Value Measurements (Detail) - Assets and Liabilities Measured at Fair Value on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Securities available-for-sale
Securities Available-for-Sale	$ 1,166,783	$ 1,294,478
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	159,835
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	159,835
US Treasury Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	159,835
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	50,182	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	50,182	501,226
U.S. Government Sponsored Entities [Member]
Securities available-for-sale
Securities Available-for-Sale	50,182	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	544,468	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	544,468	337,631
Collateralized Mortgage Backed Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	544,468	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	13,216	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	13,216	16,486
Collateralized Mortgage Obligations [Member]
Securities available-for-sale
Securities Available-for-Sale	13,216	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	152	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	152	166
Asset-backed Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	152	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	367,910	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	367,910	380,429
Corporate Debt Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	367,910	380,429
Mutual Funds Member | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	6,122	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	6,122	6,035
Mutual Funds Member
Securities available-for-sale
Securities Available-for-Sale	6,122	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	2,176	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	2,176	1,654
Preferred Stock Of Government Sponsored Entities Member
Securities available-for-sale
Securities Available-for-Sale	2,176	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	17,749	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	17,749	45,963
Trust Preferred Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	17,749	45,963
Other Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	4,973	2,960
Other Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Other Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Other Equity Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	4,973	2,960
Other Equity Securities [Member]
Securities available-for-sale
Securities Available-for-Sale	4,973	2,960
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	104,465	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	104,465	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	169	218
Warrant [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Total Assets	169	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	4	34
Liabilities
Total Liabilities	1	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	4	34
Liabilities
Total Liabilities	1	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	1,910	2,151
Liabilities
Total Liabilities	1,089	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	1,910	2,151
Liabilities
Total Liabilities	1,089	486
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Total Liabilities	0	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Total Liabilities	742	2,634
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Total Liabilities	0	0
Interest Rate Swap [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Liabilities
Total Liabilities	742	2,634
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
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Securities Available-for-Sale	170,930	8,995
Total Assets	170,930	8,997
Liabilities
Total Liabilities	0	0
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Securities Available-for-Sale	995,853	1,285,483
Total Assets	1,102,232	1,292,208
Liabilities
Total Liabilities	1,832	3,125
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Securities Available-for-Sale	0	0
Total Assets	169	218
Liabilities
Total Liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Securities available-for-sale
Securities Available-for-Sale	1,166,783	1,294,478
Total Assets	1,273,331	1,301,423
Liabilities
Total Liabilities	$ 1,832	$ 3,125