Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net change in Unrealized gains (losses), tax expense (benefit)	$ 2,870	$ (3,692)	$ 9,350	$ (893)
Reclassification adjustment for gains, tax expense	207	181	323	352
Amortization of unrealized gain on securities reclassified to held-to-maturity, tax benefit	62	120	127	120
Change in unfunded pension liability related to unrealized (loss) gain, prior service cost and transition obligation, tax (benefit) expense	$ (13)	$ (9)	$ 280	$ (18)