Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	$ 559		$ (4,135)		$ (3,543)
Other comprehensive income (loss), net of tax	150		4,694		(592)
Accumulated other comprehensive income (loss), net of tax	709		559		(4,135)
Accumulated Other Comprehensive Income (Loss), Tax [Roll Forward]
Accumulated other comprehensive income (loss), tax	(370)		2,736		2,344
Accumulated other comprehensive income (loss), tax	(469)		(370)		2,736
Unrecognized Net Actuarial Loss [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(4,068)	[1]	(4,375)	[1]	(3,650)	[1]
Other comprehensive income (loss), net of tax	755	[1]	307	[1]	(725)	[1]
Accumulated other comprehensive income (loss), net of tax	(3,313)	[1]	(4,068)	[1]	(4,375)	[1]
Accumulated Other Comprehensive Income (Loss), Tax [Roll Forward]
Other comprehensive income (loss), tax	(500)		(203)		480
Unrecognized Prior Service Credit [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	4,627	[1]	277	[1]	180	[1]
Other comprehensive income (loss), net of tax	(568)	[1]	4,350	[1]	97	[1]
Accumulated other comprehensive income (loss), net of tax	4,059	[1]	4,627	[1]	277	[1]
Accumulated Other Comprehensive Income (Loss), Tax [Roll Forward]
Other comprehensive income (loss), tax	376		(2,879)		(64)
Unrecognized Transition Asset [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	0	[1]	(37)	[1]	(73)	[1]
Other comprehensive income (loss), net of tax	0	[1]	37	[1]	36	[1]
Accumulated other comprehensive income (loss), net of tax	0	[1]	0	[1]	(37)	[1]
Accumulated Other Comprehensive Income (Loss), Tax [Roll Forward]
Other comprehensive income (loss), tax	0		(24)		(24)
Unrealized Gain (Loss) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	0		0		0
Other comprehensive income (loss), net of tax	(37)		0		0
Accumulated other comprehensive income (loss), net of tax	(37)		0		0
Accumulated Other Comprehensive Income (Loss), Tax [Roll Forward]
Other comprehensive income (loss), tax	$ 25		$ 0		$ 0

[1] Amounts pertain to our post-retirement benefit plans.