Fair Value Disclosures - Assets And Liabilities Measured At Fair Value On Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets:
Total Assets	$ 67,964	$ 93,590
Level 1
Assets:
Total Assets	8,956	29,108
Level 1 | Plan Assets
Assets:
Total Assets	8,956	29,108
Level 2
Assets:
Total Assets	59,008	64,482
Liabilities:
Total Liabilities	858,671	929,065
Level 2 | Foreign currency forward contracts
Assets:
Total Assets	1,318	2,053
Liabilities:
Total Liabilities	3,260	1,605
Level 2 | Interest rate swap contracts
Assets:
Total Assets	0	3,412
Liabilities:
Total Liabilities	10,681	0
Level 2 | Plan Assets
Assets:
Total Assets	57,690	59,017
Level 2 | Plan Liabilities
Liabilities:
Total Liabilities	68,570	89,900
Level 2 | Debt | Senior notes
Liabilities:
Total Liabilities	$ 776,160	$ 837,560