Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Consolidated Statements of Comprehensive Income
Net income	$ 28,095	$ 25,140	$ 77,105	$ 73,938
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during period	(4,388)	5,991	12,162	2,981
Tax effect	1,673	(2,284)	(4,638)	(1,137)
Reclassification adjustment for gains (losses) included in net income			(122)
Tax effect			47
Net of tax amount	(2,715)	3,707	7,449	1,844
Unrealized gains (losses) on derivative financial instruments qualifying as cash flow hedges:
Unrealized holding gains (losses) arising during period	51	(154)	(147)	(245)
Tax effect	(19)	59	56	93
Reclassification adjustment for losses included in interest expense	69	89	209	230
Tax effect	(27)	(34)	(80)	(88)
Net of tax amount	74	(40)	38	(10)
Change in pension and retiree medical plan obligation:
Reclassification adjustment for actuarial (gains) losses included in salaries and employee benefits	204	225	612	674
Tax effect	(78)	(86)	(233)	(256)
Net of tax amount	126	139	379	418
Other comprehensive income (loss), net of tax	(2,515)	3,806	7,866	2,252
Total comprehensive income	$ 25,580	$ 28,946	$ 84,971	$ 76,190