Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Income	$ 23,360	$ 21,795	$ 22,179
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(2,961)	3,500	(2,246)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	168	589	479
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(2,793)	4,089	(1,767)
Comprehensive Income (Loss), Net of Tax	20,567	25,884	20,412
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	232	(2,925)	(661)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(67)	(326)	(522)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(2,846)	6,425	(1,340)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	288	914	1,013
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(347)	0	(245)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ (53)	$ 1	$ (12)