CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 87,047	$ 80,411	$ 57,330
Change in securities available-for-sale:
Unrealized holding gain (loss) on securities available-for-sale arising during the period	23,438	(7,339)	2,245
Reclassification adjustment for (gains) losses included in net income	(142)	50	(32)
Net securities gain (loss) activity during the period	23,296	(7,289)	2,213
Tax effect	(4,893)	1,637	(707)
Net of tax amount	18,403	(5,652)	1,506
Defined benefit pension plans:
Net gain (loss) on defined benefit pension plans	(409)	269	97
Amortization of net actuarial loss	205	266	265
Net gain (loss) on activity during the period	(204)	535	362
Tax effect	51	(163)	(151)
Net of tax amount	(153)	372	211
Total other comprehensive income (loss), net of tax	18,250	(5,280)	1,717
Comprehensive income	$ 105,297	$ 75,131	$ 59,047