Note 11 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities	$ 390,009	$ 284,288
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
US Treasury Securities [Member]
Securities available-for-sale
Available-for-sale Securities	390,009	284,288
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	250,010	148,160
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale
Available-for-sale Securities	250,010	148,160
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	563,638	1,062,269
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Commercial Mortgage Backed Securities [Member]
Securities available-for-sale
Available-for-sale Securities	563,638	1,062,269
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	30	36
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Collateralized Mortgage Obligations [Member]
Securities available-for-sale
Available-for-sale Securities	30	36
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	74,469	73,855
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Corporate Debt Securities [Member]
Securities available-for-sale
Available-for-sale Securities	74,469	73,855
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities	5,926	5,833
Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities
Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Mutual Funds [Member]
Securities available-for-sale
Available-for-sale Securities	5,926	5,833
Preferred Stock of Government Sponsored Entities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities
Preferred Stock of Government Sponsored Entities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	3,188	3,216
Preferred Stock of Government Sponsored Entities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Preferred Stock of Government Sponsored Entities [Member]
Securities available-for-sale
Available-for-sale Securities	3,188	3,216
Other Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities
Other Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	11,199	8,695
Other Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Other Equity Securities [Member]
Securities available-for-sale
Available-for-sale Securities	11,199	8,695
Warrant [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Assets, Fair Value Disclosure
Warrant [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Assets, Fair Value Disclosure
Warrant [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Assets, Fair Value Disclosure	75	62
Warrant [Member]
Securities available-for-sale
Assets, Fair Value Disclosure	75	62
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Assets, Fair Value Disclosure
Liabilities
Liabilities, Fair Value Disclosure
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Assets, Fair Value Disclosure	1,711	3,339
Liabilities
Liabilities, Fair Value Disclosure	712	4,124
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Assets, Fair Value Disclosure
Liabilities
Liabilities, Fair Value Disclosure
Foreign Exchange Contract [Member]
Securities available-for-sale
Assets, Fair Value Disclosure	1,711	3,339
Liabilities
Liabilities, Fair Value Disclosure	712	4,124
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Liabilities, Fair Value Disclosure
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Liabilities, Fair Value Disclosure	15,186	6,496
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Liabilities, Fair Value Disclosure
Interest Rate Swap [Member]
Liabilities
Liabilities, Fair Value Disclosure	15,186	6,496
Option Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Liabilities, Fair Value Disclosure
Option Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Liabilities, Fair Value Disclosure		28
Option Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Liabilities, Fair Value Disclosure
Option Contracts [Member]
Liabilities
Liabilities, Fair Value Disclosure		28
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Available-for-sale Securities	395,935	290,121
Assets, Fair Value Disclosure	395,935	290,121
Liabilities
Liabilities, Fair Value Disclosure
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Available-for-sale Securities	902,534	1,296,231
Assets, Fair Value Disclosure	904,245	1,299,570
Liabilities
Liabilities, Fair Value Disclosure	15,898	10,648
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Available-for-sale Securities
Assets, Fair Value Disclosure	75	62
Liabilities
Liabilities, Fair Value Disclosure
Available-for-sale Securities	1,298,469	1,586,352
Assets, Fair Value Disclosure	1,300,255	1,589,753
Liabilities, Fair Value Disclosure	$ 15,898	$ 10,648