Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (7,475)	$ (17,605)
Other comprehensive income (loss) before reclassifications	(3,655)	10,488
Amounts reclassified from accumulated other comprehensive income	391	(358)
Other comprehensive income (loss), net of tax	(3,264)	10,130	$ (17,282)
Ending balance	(10,739)	(7,475)	(17,605)
Unrealized Gains (Losses) on Available-For-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(3,017)	(14,476)
Other comprehensive income (loss) before reclassifications	(2,159)	12,060
Amounts reclassified from accumulated other comprehensive income	0	(601)
Other comprehensive income (loss), net of tax	(2,159)	11,459
Ending balance	(5,176)	(3,017)	(14,476)
Interest Rate Swaps [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(324)	0
Other comprehensive income (loss) before reclassifications	(149)	(331)
Amounts reclassified from accumulated other comprehensive income	7	7
Other comprehensive income (loss), net of tax	(142)	(324)
Ending balance	(466)	(324)	0
Defined Benefit Plan Items [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(4,134)	(3,129)
Other comprehensive income (loss) before reclassifications	(1,347)	(1,241)
Amounts reclassified from accumulated other comprehensive income	384	236
Other comprehensive income (loss), net of tax	(963)	(1,005)
Ending balance	$ (5,097)	$ (4,134)	$ (3,129)