Note 13 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Securities available-for-sale	$ 1,146,102	$ 1,451,842
Equity securities	24,570	28,005
Assets, fair value disclosure	1,176,056	1,484,478
Liabilities, fair value disclosure	34,297	15,651
Equity securities	24,570	28,005
US Treasury Securities [Member]
Securities available-for-sale	99,927	74,936
US Government Corporations and Agencies Securities [Member]
Securities available-for-sale	107,393
US Government Agencies Debt Securities [Member]
Securities available-for-sale		90,796
Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	802,412	887,790
US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale		224,443
Collateralized Mortgage Obligations [Member]
Securities available-for-sale	301	552
Corporate Debt Securities [Member]
Securities available-for-sale	136,069	173,325
Mutual Funds [Member]
Equity securities	6,431	6,277
Equity securities	6,431	6,277
Preferred Stock of Government Sponsored Entities [Member]
Equity securities	4,868	10,529
Equity securities	4,868	10,529
Other Equity Securities [Member]
Equity securities	13,271	11,199
Equity securities	13,271	11,199
Warrant [Member]
Assets, fair value disclosure	13	39
Interest Rate Swap [Member]
Assets, fair value disclosure	3,842	2,181
Liabilities, fair value disclosure	33,760	14,229
Foreign Exchange Contract [Member]
Assets, fair value disclosure	1,529	2,411
Liabilities, fair value disclosure	531	1,415
Option Contracts [Member]
Liabilities, fair value disclosure	6	7
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale	99,927	74,936
Equity securities	24,570	28,005
Assets, fair value disclosure	124,497	102,941
Liabilities, fair value disclosure	0	0
Equity securities	24,570	28,005
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Securities available-for-sale	99,927	74,936
Fair Value, Inputs, Level 1 [Member] | US Government Corporations and Agencies Securities [Member]
Securities available-for-sale	0
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]
Securities available-for-sale		0
Fair Value, Inputs, Level 1 [Member] | Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 1 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale		0
Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 1 [Member] | Mutual Funds [Member]
Equity securities	6,431	6,277
Equity securities	6,431	6,277
Fair Value, Inputs, Level 1 [Member] | Preferred Stock of Government Sponsored Entities [Member]
Equity securities	4,868	10,529
Equity securities	4,868	10,529
Fair Value, Inputs, Level 1 [Member] | Other Equity Securities [Member]
Equity securities	13,271	11,199
Equity securities	13,271	11,199
Fair Value, Inputs, Level 1 [Member] | Warrant [Member]
Assets, fair value disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member]
Assets, fair value disclosure	0	0
Liabilities, fair value disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Foreign Exchange Contract [Member]
Assets, fair value disclosure	0	0
Liabilities, fair value disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Option Contracts [Member]
Liabilities, fair value disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	1,046,175	1,376,906
Equity securities	0	0
Assets, fair value disclosure	1,051,546	1,381,498
Liabilities, fair value disclosure	34,297	15,651
Equity securities	0	0
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 2 [Member] | US Government Corporations and Agencies Securities [Member]
Securities available-for-sale	107,393
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Securities available-for-sale		90,796
Fair Value, Inputs, Level 2 [Member] | Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	802,412	887,790
Fair Value, Inputs, Level 2 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale		224,443
Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations [Member]
Securities available-for-sale	301	552
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Securities available-for-sale	136,069	173,325
Fair Value, Inputs, Level 2 [Member] | Mutual Funds [Member]
Equity securities	0	0
Equity securities	0	0
Fair Value, Inputs, Level 2 [Member] | Preferred Stock of Government Sponsored Entities [Member]
Equity securities	0	0
Equity securities	0	0
Fair Value, Inputs, Level 2 [Member] | Other Equity Securities [Member]
Equity securities	0	0
Equity securities	0	0
Fair Value, Inputs, Level 2 [Member] | Warrant [Member]
Assets, fair value disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Assets, fair value disclosure	3,842	2,181
Liabilities, fair value disclosure	33,760	14,229
Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Contract [Member]
Assets, fair value disclosure	1,529	2,411
Liabilities, fair value disclosure	531	1,415
Fair Value, Inputs, Level 2 [Member] | Option Contracts [Member]
Liabilities, fair value disclosure	6	7
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale	0	0
Equity securities	0	0
Assets, fair value disclosure	13	39
Liabilities, fair value disclosure	0	0
Equity securities	0	0
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Corporations and Agencies Securities [Member]
Securities available-for-sale	0
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member]
Securities available-for-sale		0
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 3 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale		0
Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Securities available-for-sale	0	0
Fair Value, Inputs, Level 3 [Member] | Mutual Funds [Member]
Equity securities	0	0
Equity securities	0	0
Fair Value, Inputs, Level 3 [Member] | Preferred Stock of Government Sponsored Entities [Member]
Equity securities	0	0
Equity securities	0	0
Fair Value, Inputs, Level 3 [Member] | Other Equity Securities [Member]
Equity securities	0	0
Equity securities	0	0
Fair Value, Inputs, Level 3 [Member] | Warrant [Member]
Assets, fair value disclosure	13	39
Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member]
Assets, fair value disclosure	0	0
Liabilities, fair value disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Foreign Exchange Contract [Member]
Assets, fair value disclosure	0	0
Liabilities, fair value disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Option Contracts [Member]
Liabilities, fair value disclosure	$ 0	$ 0