Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss)
Balance			$ 405,473
Total other comprehensive loss	$ (2,546)	$ (8,039)	(8,679)	$ (7,041)
Balance	405,395		405,395
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss)
Balance			(27,510)	(1,140)
Other comprehensive income (loss) before reclassifications			(9,361)	(7,300)
Amounts reclassified from other comprehensive income (loss)			682	259
Total other comprehensive loss			(8,679)	(7,041)
Balance	(36,189)	(8,181)	(36,189)	(8,181)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss)
Balance			1,943	16,793
Other comprehensive income (loss) before reclassifications			(9,462)	(8,112)
Total other comprehensive loss			(9,462)	(8,112)
Balance	(7,519)	8,681	(7,519)	8,681
Defined Benefit Pension Plan Adjustments
Accumulated Other Comprehensive Income (Loss)
Balance			(30,358)	(18,450)
Other comprehensive income (loss) before reclassifications			103	254
Amounts reclassified from other comprehensive income (loss)	458	192	1,357	571
Total other comprehensive loss			1,460	825
Balance	(28,898)	(17,625)	(28,898)	(17,625)
Derivatives
Accumulated Other Comprehensive Income (Loss)
Balance			905	517
Other comprehensive income (loss) before reclassifications			(2)	558
Amounts reclassified from other comprehensive income (loss)			(675)	(312)
Total other comprehensive loss			(677)	246
Balance	$ 228	$ 763	$ 228	$ 763