Note 14 - Accumulated Other Comprehensive Income (Loss) - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Tax (expense) benefit		$ (3,272)		$ (4,489)		$ (5,559)	$ (7,439)
Net of tax		10,556	$ 7,068	13,923	$ 11,412	17,624	25,335
Other expense		29,566		20,653		57,576	38,830
Other expense		3,338		3,749		7,965	8,440
Total before tax		13,828		18,412		23,183	32,774
Reclassification out of Accumulated Other Comprehensive Income [Member]
Tax (expense) benefit		3		40		6	78
Net of tax		(8)		(84)		(15)	(168)
Total before tax		(11)		(124)		(21)	(246)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Net loss on sale of securities		(15)				(15)
Tax (expense) benefit		5				5
Net of tax		(10)				(10)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] | Interest Rate Swap [Member]
Tax (expense) benefit		(200)		86		(262)	110
Net of tax		447		(187)		586	(241)
Other expense		647		(273)		848	(351)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Other expense	[1]	(31)		(133)		(63)	(265)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Other expense	[1]	$ 20		$ 9		$ 42	$ 19

[1] These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (See Note 9 of the Notes to Consolidated Financial Statements "Pension and Other Postretirement Benefit Plans".)