CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net change in unrealized gains (losses) on available-for-sale securities, net of tax of ($2,975), $847, ($5,960) and $3,971, respectively	$ (2,975)	$ 847	$ (5,960)	$ 3,971
Net reclassification adjustment for net gains included in net income, net of tax of $6, $7, $6 and $7, respectively(1)	6	7	6	7
Net change in unrealized losses on cash flow hedging derivatives, net of tax of $330, ($123), $583 and ($430), respectively	330	(123)	583	(430)
Net reclassification adjustment for effective portion of cash flow hedges, net of tax of ($44), ($44), ($69) and ($105), respectively(2)	(44)	(44)	(69)	(105)
Reclassification of amortization of net unrecognized actuarial loss and prior service cost, net of tax of ($13), ($32), ($26) and ($63), respectively(3)	$ (13)	$ (32)	$ (26)	$ (63)