Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Consolidated Statements of Comprehensive Income
Net income	$ 47,082	$ 35,046	$ 129,867	$ 85,133
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during period	(11,056)	130	(41,354)	7,049
Tax effect	2,432	(50)	9,130	(2,687)
Reclassification adjustment for (gains) losses and OTTI included in net income	11	(525)	652	(635)
Tax effect	(2)	200	(144)	242
Net of tax amount	(8,615)	(245)	(31,716)	3,969
Unrealized gains (losses) on derivative financial instruments qualifying as cash flow hedges:
Unrealized holding gains (losses) arising during period	(1)	4	43	(56)
Tax effect		(1)	(9)	21
Reclassification adjustment for losses included in interest expense	35	57	121	226
Tax effect	(8)	(22)	(27)	(86)
Net of tax amount	26	38	128	105
Change in pension plan obligation:
Reclassification adjustment for changes included in net income	194	188	581	564
Tax effect	(43)	(72)	(128)	(215)
Net of tax amount	151	116	453	349
Net comprehensive income (loss)	(8,438)	(91)	(31,135)	4,423
Comprehensive income	$ 38,644	$ 34,955	$ 98,732	$ 89,556