Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Consolidated Statements of Comprehensive Income
Net income	$ 51,565	$ 47,082	$ 137,392	$ 129,867
Unrealized gains (losses) on available for sale securities:
Unrealized holding gains (losses) arising during period	7,467	(11,056)	44,528	(41,354)
Tax effect	(1,643)	2,432	(9,796)	9,130
Reclassification adjustment for (gains) losses included in net income	(437)	11	2,679	652
Tax effect	96	(2)	(590)	(144)
Net of tax amount	5,483	(8,615)	36,821	(31,716)
Unrealized gains (losses) on derivative financial instruments qualifying as cash flow hedges:
Unrealized holding gains (losses) arising during period	(4,988)	(1)	(18,931)	43
Tax effect	1,097		4,165	(9)
Reclassification adjustment for gains (losses) included in interest expense	(241)	35	(585)	121
Tax effect	53	(8)	128	(27)
Net of tax amount	(4,079)	26	(15,223)	128
Change in pension plan obligation:
Reclassification adjustment for changes included in net income		194	7,888	581
Tax effect		(43)	(1,735)	(128)
Net of tax amount		151	6,153	453
Other comprehensive income (loss), net of tax	1,404	(8,438)	27,751	(31,135)
Comprehensive income	$ 52,969	$ 38,644	$ 165,143	$ 98,732