Accumulated Other Comprehensive Loss - Summary of Accumulated Other Comprehensive Loss in Equity (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net actuarial loss and prior service credit	$ (20,686)		$ (21,524)
Less: deferred tax benefit	4,396		4,574
Net of tax	(16,290)		(16,950)
Interest rate swap	195		220
Less: deferred tax liability	(78)		(88)
Net of tax	117		132
Foreign currency translation adjustment	(626)		1,206
Total accumulated other comprehensive loss	$ (16,799)	$ (14,394)	$ (15,612)	$ (14,785)	$ (16,314)	$ (14,614)