Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (2,902)	$ (1,929)	$ (2,902)	$ (1,929)	$ (2,813)	$ (2,952)	$ (1,495)	$ (1,565)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	50	(434)	(89)	(364)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0	0
Other comprehensive income (loss), net of Tax	50	(434)	(89)	(364)	(1,248)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), net of Tax			(89)		(1,248)
Pension and Other Postretirement Plans Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(2,863)	(2,215)	(2,863)	(2,215)	(3,175)	(2,877)	(2,165)	(2,287)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	14	(50)	312	72
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0	0
Other comprehensive income (loss), net of Tax	14	(50)	312	72
Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(39)	286	(39)	286	$ 362	$ (75)	$ 670	$ 722
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	36	(384)	(401)	(436)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0	0
Other comprehensive income (loss), net of Tax	$ 36	$ (384)	$ (401)	$ (436)