Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net change in unrealized gains (losses), tax expense (benefit)	$ 3,787	$ (477)	$ 2,892	$ 11,060
Reclassification adjustment for gains, tax expense	(29)	(13)	(381)	(371)
Amortization of unrealized gain on securities reclassified to held-to-maturity, tax benefit	(55)	0	(175)	0
Change in unfunded pension liability related to unrealized (loss) gain, prior service cost and transition obligation, tax (benefit) expense	$ (9)	$ 3	$ (27)	$ 39