CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 16,497	$ 13,427	$ 11,540
Other comprehensive income (loss):
Change in net unrealized holding gains (losses) on available-for-sale securities and I/O strips	(3,809)	7,164	(14,302)
Deferred income taxes	1,605	(3,012)	6,007
Change in net unamortized unrealized gain on securities available-for-sale that were reclassified to securities held-to-maturity	(55)	(54)	(54)
Deferred income taxes	23	23	23
Reclassification adjustment for gains realized in income	(642)	(97)	(38)
Deferred income taxes	270	41	16
Change in unrealized gains (losses) on securities and I/O strips, net of deferred income taxes	(2,608)	4,065	(8,348)
Change in net pension and other benefit plan liability adjustment	(3,036)	(3,253)	2,825
Deferred income taxes	1,275	1,366	(1,187)
Change in pension and other benefit plan liability, net of deferred income taxes	(1,761)	(1,887)	1,638
Other comprehensive income (loss)	(4,369)	2,178	(6,710)
Total comprehensive income	$ 12,128	$ 15,605	$ 4,830