CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net change in unrealized gains on available-for-sale securities, tax effect	$ 405	$ (1,649)	$ (5,599)	$ (1,723)
Net change in unrealized loss on cash flow hedging derivatives, tax effect	0	1	1	1
Net reclassification adjustment for effective portion of cash flow hedges included in interest expense, tax effect	(107)	1,221	1,859	1,115
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	(187)	(271)	(532)	(447)
Reclassification of amortization of prior service cost included in net periodic cost, tax effect	$ (20)	$ (20)	$ (62)	$ (61)