Other Comprehensive (Loss) Income - Changes in 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), Net Of Tax [Roll Forward]
Beginning balance	$ 29	$ (4,851)
Current period other comprehensive (loss) income	(2,575)	4,880	$ (12,567)
Other comprehensive loss, net of tax	(2,575)	4,880	(12,567)
Ending balance	(2,546)	29	(4,851)
Unrealized Gains on Securities Available for Sale [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	7,743	(2,799)
Current period other comprehensive (loss) income	(3,792)	10,542
Ending balance	3,951	7,743	(2,799)
Post-Retirement Obligations [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	(7,714)	(2,052)
Current period other comprehensive (loss) income	1,290	(5,662)
Ending balance	(6,424)	(7,714)	$ (2,052)
Accumulated Unrealized Gain (Loss) on Derivatives Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	0
Other comprehensive loss, net of tax	(73)
Ending balance	$ (73)	$ 0