Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net change in unrealized gain (loss) on available-for-sale securities, tax effect	$ 1,017	$ 1,212	$ 1,873
Net reclassification adjustment for gains included in net income, tax effect	299	18	1
Net change in unrealized gains (losses) on cash flow hedging derivatives, tax effect	134	343	825
Net reclassification adjustments for effective portion of cash flow hedges included in interest expense, tax effect	(557)	(709)	(593)
Net actuarial (loss) gain, tax effect	723	127	21
Reclassification of amortization of net unrecognized actuarial loss and of prior service cost included in net periodic cost, tax effect	$ (92)	$ (83)	$ (84)