Consolidated Statements of Comprehensive Income - 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 Income	$ 12,722	$ 14,426	$ 45,970	$ 39,549
Net change in unrealized (losses) gains on investment securities available for sale
Net unrealized (losses) gains arising during the period, net of tax (benefit) expense of ($682), $3,787, $8,668 and $2,892 respectively	(1,112)	6,178	14,143	4,721
Less: reclassification adjustment for net gains on sales realized in net income, net of tax expense of $395, $29, $718 and $381, respectively	(645)	(47)	(1,172)	(623)
Net change in unrealized gains (losses) on investment securities available-for-sale	(1,757)	6,131	12,971	4,098
Net change in securities held-to-maturity
Amortization of unrealized gain on securities reclassified to held-to-maturity, net of tax expense of $60, $55, $187, $175, respectively	(102)	(104)	(305)	(312)
Net change in unfunded pension liability
Change in unfunded pension liability related to unrealized (loss) gain, prior service cost and transition obligation, net of tax (benefit) expense of ($14), ($9), $266 and ($27), respectively	(20)	(15)	436	(45)
Net change in cash flow hedge
Net unrealized gain arising during the period, net of tax expense of $38, $0, $38, and $0, respectively	61		61
Total other comprehensive (loss) income	(1,818)	6,012	13,163	3,741
Total comprehensive income	$ 10,904	$ 20,438	$ 59,133	$ 43,290