Comprehensive Income Changes in Accumulated Other Comprehensive Income By Componenet (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Loss, Beginning Balance	$ (7,166)	$ (4,373)	$ 8,462
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(1,208)	(2,961)	3,500
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	402	168	589
Other Comprehensive (Loss) Income	(806)	(2,793)	4,089
Accumulated Other Comprehensive Income (Loss), Net of Tax	(7,972)	(7,166)	(4,373)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Loss, Beginning Balance	2,539	2,374	5,625
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(1,832)	232	(2,925)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(78)	(67)	(326)
Other Comprehensive (Loss) Income	(1,910)	165	(3,251)
Accumulated Other Comprehensive Income (Loss), Net of Tax	629	2,539	2,374
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Loss, Beginning Balance	(9,255)	(6,697)	(14,036)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	848	(2,846)	6,425
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	514	288	914
Other Comprehensive (Loss) Income	1,362	(2,558)	7,339
Accumulated Other Comprehensive Income (Loss), Net of Tax	(7,893)	(9,255)	(6,697)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Loss, Beginning Balance	(450)	(50)	(51)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(224)	(347)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(34)	(53)	1
Other Comprehensive (Loss) Income	(258)	(400)	1
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (708)	$ (450)	$ (50)