Financial Instruments (Financial Instruments Assets (Liabilities) Measured At Fair Value) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financial Instruments And Fair Value Measurements [Line Items]
Cash and cash equivalents, Carrying Amount		$ 96,202	$ 96,101	$ 63,551
Loans payable, Carrying Amount			(50)
Long-term debt, Carrying Amount		(807,565)	(814,952)
Foreign currency forward contracts, net, Carrying amount		601	(270)
Cash and cash equivalents, Fair Value		96,202	96,101
Loans payable, Fair Value			(50)
Foreign currency forward contracts, net, Fair Value		601	(270)
Unamortized debt issuance costs		3,886
Cross Currency Swaps [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Cross currency swaps, Carrying Amount		22,111	17,104
Cross currency swaps, Fair Value		22,111	17,104
Interest Rate Swap [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Interest rate swaps-liabilities, Carrying Amount		(14,698)	(5,244)
Interest rate swaps-liabilities, Fair Value		(14,698)	(5,244)
Term Loan Facility - Amended Credit Facility [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Carrying Amount	[1]	(801,764)	(809,022)
Long-term debt, Fair Value	[1]	(799,750)	(796,796)
Unamortized debt issuance costs		3,900	4,800
Other Long-Term Notes Payable [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Carrying Amount		(3,496)	(4,098)
Long-term debt, Fair Value		(1,557)	(1,772)
Level 1 [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Cash and cash equivalents, Fair Value		96,202	96,101
Foreign currency forward contracts, net, Fair Value
Level 1 [Member] | Cross Currency Swaps [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Cross currency swaps, Fair Value
Level 1 [Member] | Interest Rate Swap [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Interest rate swaps-liabilities, Fair Value
Level 1 [Member] | Term Loan Facility - Amended Credit Facility [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Fair Value	[1]
Level 1 [Member] | Other Long-Term Notes Payable [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Fair Value
Level 2 [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Loans payable, Fair Value			(50)
Foreign currency forward contracts, net, Fair Value		601	(270)
Level 2 [Member] | Cross Currency Swaps [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Cross currency swaps, Fair Value		22,111	17,104
Level 2 [Member] | Interest Rate Swap [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Interest rate swaps-liabilities, Fair Value		(14,698)	(5,244)
Level 2 [Member] | Term Loan Facility - Amended Credit Facility [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Fair Value	[1]	(799,750)	(796,796)
Level 2 [Member] | Other Long-Term Notes Payable [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Fair Value		(1,557)	$ (1,772)
Level 3 [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Cash and cash equivalents, Fair Value
Foreign currency forward contracts, net, Fair Value
Level 3 [Member] | Cross Currency Swaps [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Cross currency swaps, Fair Value
Level 3 [Member] | Interest Rate Swap [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Interest rate swaps-liabilities, Fair Value
Level 3 [Member] | Term Loan Facility - Amended Credit Facility [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Fair Value	[1]
Level 3 [Member] | Other Long-Term Notes Payable [Member]
Financial Instruments And Fair Value Measurements [Line Items]
Long-term debt, Fair Value

[1] The carrying values of the term loan facilities are net of unamortized debt issuance costs of $3.9 million and $4.8 million for the period ended December 31, 2019, and December 31, 2018, respectively.