CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income		$ 80,411	$ 57,330	$ 52,084
Change in securities available for sale:
Unrealized holding gain (loss) on securities available for sale arising during the period		(7,339)	2,245	(7,238)
Reclassification adjustment for (gains)/losses included in net income		50	(32)	(66)
Net securities gain (loss) activity during the period		(7,289)	2,213	(7,304)
Tax effect		1,637	(707)	2,746
Net of tax amount		(5,652)	1,506	(4,558)
Defined benefit pension plans:
Net gain(loss) on defined benefit pension plans		269	97	(151)
Amortization of net actuarial loss	[1]	266	265	215
Net gain on activity during the period		535	362	64
Tax effect		(163)	(151)	(35)
Net of tax amount		372	211	29
Total other comprehensive income (loss), net of tax		(5,280)	1,717	(4,529)
Comprehensive income		$ 75,131	$ 59,047	$ 47,555

[1] Included in the computation of net pension plan expense as more fully discussed in Note 11.