Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Total [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance January 1, 2016	$ (10,739)	$ (7,475)
Other comprehensive income (loss) before reclassifications	4,029	1,337
Amounts reclassified from accumulated other comprehensive income	2	2
Net current period other comprehensive income (loss)	4,031	1,339
Ending balance March 31, 2016	(6,708)	(6,136)
Unrealized Gains (Losses) on Available-For-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance January 1, 2016	(5,176)	(3,017)
Other comprehensive income (loss) before reclassifications	4,634	1,660
Amounts reclassified from accumulated other comprehensive income	0	0
Net current period other comprehensive income (loss)	4,634	1,660
Ending balance March 31, 2016	(542)	(1,357)
Interest Rate Swaps [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance January 1, 2016	(466)	(324)
Other comprehensive income (loss) before reclassifications	(551)	(323)
Amounts reclassified from accumulated other comprehensive income	2	2
Net current period other comprehensive income (loss)	(549)	(321)
Ending balance March 31, 2016	(1,015)	(645)
Defined Benefit Plan Items [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance January 1, 2016	(5,097)	(4,134)
Other comprehensive income (loss) before reclassifications	(54)	0
Amounts reclassified from accumulated other comprehensive income	0	0
Net current period other comprehensive income (loss)	(54)	0
Ending balance March 31, 2016	$ (5,151)	$ (4,134)