Note 15 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Securities available-for-sale	$ 1,314,345	$ 1,586,352	[1]
Assets, fair value disclosure	1,316,664	1,589,753
Liabilities, fair value disclosure	6,997	10,648
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	513,376	302,032	[1]
Assets, fair value disclosure	513,376	302,032
Liabilities, fair value disclosure
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	800,969	1,284,320	[1]
Assets, fair value disclosure	803,209	1,287,659
Liabilities, fair value disclosure	6,997	10,648
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale			[1]
Assets, fair value disclosure	79	62
Liabilities, fair value disclosure
US Treasury Securities [Member]
Securities available-for-sale	489,017	284,288
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	489,017	284,288
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale	390,331	148,160
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	390,331	148,160
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	336,260	1,062,269
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	336,260	1,062,269
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Collateralized Mortgage Obligations [Member]
Securities available-for-sale	28	36
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	28	36
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Corporate Debt Securities [Member]
Securities available-for-sale	74,350	73,855
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	74,350	73,855
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Mutual Funds [Member]
Securities available-for-sale	6,230	5,833
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	6,230	5,833
Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale
Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Preferred Stock of Government Sponsored Entities [Member]
Securities available-for-sale	7,308	3,216	[2]
Preferred Stock of Government Sponsored Entities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	7,308	3,216	[2]
Preferred Stock of Government Sponsored Entities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale			[2]
Preferred Stock of Government Sponsored Entities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale			[2]
Other Equity Securities [Member]
Securities available-for-sale	10,821	8,695	[2]
Other Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	10,821	8,695	[2]
Other Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale			[2]
Other Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Warrant [Member]
Assets, fair value disclosure	79	62
Warrant [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value disclosure
Warrant [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value disclosure
Warrant [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value disclosure	79	62
Interest Rate Swap [Member]
Assets, fair value disclosure	938
Liabilities, fair value disclosure	3,744	6,496
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value disclosure
Liabilities, fair value disclosure
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value disclosure	938
Liabilities, fair value disclosure	3,744	6,496
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value disclosure
Liabilities, fair value disclosure
Foreign Exchange Contract [Member]
Assets, fair value disclosure	1,302	3,339
Liabilities, fair value disclosure	3,132	4,124
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value disclosure
Liabilities, fair value disclosure
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value disclosure	1,302	3,339
Liabilities, fair value disclosure	3,132	4,124
Foreign Exchange Contract [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value disclosure
Liabilities, fair value disclosure
Option Contracts [Member]
Liabilities, fair value disclosure	121	28
Option Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities, fair value disclosure
Option Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities, fair value disclosure	121	28
Option Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities, fair value disclosure

[1] Preferred stock of government sponsored entities and other equity securities as of December 31, 2015 were reclassified as level 1 rather than level 2 as originally classified due to the availability of quoted prices in active markets.

[2] Preferred stock of government sponsored entities and other equity securities as of December 31, 2015 were reclassified as level 1 rather than level 2 as originally classified due to the availability of quoted prices in active markets.