Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 5,621		$ (12,044)		$ 20,149
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	17,922		(32,159)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(257)	[1]	(34)	[1]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	17,665		(32,193)		(4,984)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	7,462		(10,108)		20,918
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	17,922		(30,727)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(352)	[1]	(299)	[1]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	17,570		(31,026)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1,841)		(1,936)		(769)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0		(1,432)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	95	[1]	265	[1]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 95		$ (1,167)

[1] (2) See following table for details about these reclassifications.