Comprehensive Income (Loss) Components of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance	$ (9,934)
Net current-period other comprehensive income	286	$ 981	$ 942
Ending Balance	(9,648)	(9,934)
Total
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance	(9,934)	(8,772)
Other comprehensive income before reclassifications	(35)	270
Amounts reclassified from AOCL	(131)	213
Net current-period other comprehensive income	286	981
Ending Balance	(9,648)	(9,934)	(8,772)
Total | Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCL	452	498
Foreign Currency Translation
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance	1,448	1,178
Other comprehensive income before reclassifications	(35)	270
Amounts reclassified from AOCL	0	0
Net current-period other comprehensive income	(35)	270
Ending Balance	1,413	1,448	1,178
Foreign Currency Translation | Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCL	0	0
Pension and Postretirement Medical Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance	251	31
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCL	(131)	213
Net current-period other comprehensive income	(131)	213
Ending Balance	120	251	31
Pension and Postretirement Medical Plans | Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCL	0	0
Interest Rate Derivative Instruments Designated as Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance	(11,633)	(9,981)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCL	0	0
Net current-period other comprehensive income	452	498
Ending Balance	(11,181)	(11,633)	$ (9,981)
Interest Rate Derivative Instruments Designated as Cash Flow Hedges | Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCL	$ 452	498
Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification of certain tax effects from AOCL		(2,143)
Foreign Currency Translation
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification of certain tax effects from AOCL		0
Pension and Postretirement Medical Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification of certain tax effects from AOCL		7
Interest Rate Derivative Instruments Designated as Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification of certain tax effects from AOCL		$ (2,150)