Note 11 - Fair Value Measurements (Details) - Assets and Liabilities Measured at Fair Value on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Securities available-for-sale
Available-for-sale Securities - Fair Value	$ 1,339,989	$ 1,586,668
Total Assets	1,343,448	1,597,816
Liabilities
Total Liabilities	2,048	6,140
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	577,242	465,917
Total Assets	577,242	465,917
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	762,747	1,120,751
Total Assets	766,185	1,131,869
Liabilities
Total Liabilities	2,048	6,140
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	21	30
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	565,163	460,193
US Treasury Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	565,163	460,193
Mortgage-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	656,869	952,815
Mortgage-backed Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	656,869	952,815
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	46	6,106
Collateralized Mortgage Obligations [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	46	6,106
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	94,337	150,304
Corporate Debt Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	94,337	150,304
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	5,833	5,724
Mutual Funds [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	5,833	5,725
Preferred Stock Of Government Sponsored Entities Member | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	11,495	11,403
Preferred Stock Of Government Sponsored Entities Member
Securities available-for-sale
Available-for-sale Securities - Fair Value	11,495	11,403
Other Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	6,246
Other Equity Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	6,246
Warrant [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	21	30
Warrant [Member]
Securities available-for-sale
Total Assets	21	30
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	3,438	6,182
Liabilities
Total Liabilities	1,594	6,140
Foreign Exchange Contract [Member]
Securities available-for-sale
Total Assets	3,438	6,182
Liabilities
Total Liabilities	1,594	6,140
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Total Liabilities	454
Interest Rate Swap [Member]
Liabilities
Total Liabilities	454
Trust Preferred Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value		123
Trust Preferred Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value		123
Trading Securities Member | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets		4,936
Trading Securities Member
Securities available-for-sale
Total Assets		$ 4,936