Fair Value Measurements - Financial Instruments Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Liabilities
Contingent consideration	$ (2,655)	$ (66)
Foreign currency exchange contracts
Assets
Foreign currency exchange contracts		1,473
Interest rate cap contracts
Assets
Interest rate derivatives	854	2,460
Interest rate swap agreements
Liabilities
Swap agreements	(6,625)	(9,116)
Cross-currency swap agreements
Liabilities
Swap agreements	(6,686)
Level 1
Liabilities
Contingent consideration	0	0
Level 1 | Foreign currency exchange contracts
Assets
Foreign currency exchange contracts		0
Level 1 | Interest rate cap contracts
Assets
Interest rate derivatives	0	0
Level 1 | Interest rate swap agreements
Liabilities
Swap agreements	0	0
Level 1 | Cross-currency swap agreements
Liabilities
Swap agreements	0
Level 2
Liabilities
Contingent consideration	0	0
Level 2 | Foreign currency exchange contracts
Assets
Foreign currency exchange contracts		1,473
Level 2 | Interest rate cap contracts
Assets
Interest rate derivatives	854	2,460
Level 2 | Interest rate swap agreements
Liabilities
Swap agreements	(6,625)	(9,116)
Level 2 | Cross-currency swap agreements
Liabilities
Swap agreements	(6,686)
Level 3
Liabilities
Contingent consideration	(2,655)	(66)
Level 3 | Foreign currency exchange contracts
Assets
Foreign currency exchange contracts		0
Level 3 | Interest rate cap contracts
Assets
Interest rate derivatives	0	0
Level 3 | Interest rate swap agreements
Liabilities
Swap agreements	0	$ 0
Level 3 | Cross-currency swap agreements
Liabilities
Swap agreements	$ 0