Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other comprehensive income, net of tax:
Unrealized net holding gains arising during the period, pre-tax amounts	$ 2,528	$ 3,730	$ 3,364	$ 16,941
Reclassification adjustment for net (gains) related to securities available for sale included in net income, pre-tax amounts	2	1	2	30
Reclassification adjustment for an impairment write-down of equity security, pre-tax amounts	0	0	1,312	0
Unrealized loss on derivatives (cash flow hedged) (pre-tax amounts)	(434)	(62)	(104)	(62)
Amortization of unrealized net gains related to the reclassification of available for sale investment securities to held to maturity, pre-tax amounts	225	280	463	576
Amortization of prior service cost and actuarial loss, pre-tax amounts	$ 435	$ 513	$ 870	$ 1,024