Capital Structure and Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Loss (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 1,044,820
Other comprehensive loss before reclassifications	(6,070)
Amounts reclassed from accumulated other comprehensive loss	1,236
Ending Balance	705,217
Unrealized loss on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,621)
Other comprehensive loss before reclassifications	(1,432)
Amounts reclassed from accumulated other comprehensive loss	0
Ending Balance	(3,053)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(620)
Other comprehensive loss before reclassifications	(188)
Amounts reclassed from accumulated other comprehensive loss	0
Ending Balance	(808)
Pension and other post-retirement benefits liability
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(12,779)
Other comprehensive loss before reclassifications	(4,450)
Amounts reclassed from accumulated other comprehensive loss	1,236
Ending Balance	(15,993)
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(15,020)
Ending Balance	$ (19,854)