Note 11 - Fair Value Measurements (Details) - Assets and Liabilities Measured at Fair Value on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Securities available-for-sale
Available-for-sale Securities - Fair Value	$ 1,340,092	$ 1,586,668
Total Assets	1,342,482	1,597,816
Liabilities
Total Liabilities	4,717	6,140
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	540,088	460,193
US Treasury Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	540,088	460,193
Mortgage-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	683,324	952,815
Mortgage-backed Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	683,324	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	5,817	5,724
Mutual Funds [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	5,817	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	9,252	11,403
Preferred Stock of Government Sponsored Entities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	9,252	11,403
Other Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	7,228
Other Equity Securities [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	7,228
Warrant [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	12	30
Warrant [Member]
Securities available-for-sale
Total Assets	12	30
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	442
Liabilities
Total Liabilities	280
Interest Rate Swap [Member]
Securities available-for-sale
Total Assets	442
Liabilities
Total Liabilities	280
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Total Assets	1,936	6,182
Liabilities
Total Liabilities	4,437	6,140
Foreign Exchange Contract [Member]
Securities available-for-sale
Total Assets	1,936	6,182
Liabilities
Total Liabilities	4,437	6,140
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
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	553,133	465,917
Total Assets	553,133	465,917
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities - Fair Value	786,959	1,120,751
Total Assets	789,337	1,131,869
Liabilities
Total Liabilities	4,717	6,140
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Total Assets	$ 12	$ 30