Investments in Affiliates - Equity Method Investment Summarized Balance Sheet Information (Details) - Joint Venture Unconsolidated [Member] - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Investments In And Advances To Affiliates [Line Items]
Equity Method Investment, Summarized Financial Information, Current Assets		$ 137,041	$ 141,930	$ 27,674
Equity Method Investment, Summarized Financial Information, Noncurrent Assets		179,377	170,172	95,888
Equity Method Investment, Summarized Financial Information, Assets		316,418	312,102	123,562
Equity Method Investment, Summarized Financial Information, Current Liabilities		65,848	55,816	36,625
Equity Method Investment, Summarized Financial Information, Long-term Liabilities	[1]	75,949	63,098	17,300
Equity Method Investment, Summarized Financial Information, Total Liabilities		141,797	118,914	53,925
Equity Method Investments Summarized Financial Information Net Assets		174,621	193,188	69,637
Other Affiliates [Member]
Investments In And Advances To Affiliates [Line Items]
Equity Method Investment, Summarized Financial Information, Assets		316,400
Equity Method Investments		$ 81,034	$ 84,354	$ 38,682

[1] The balance primarily relates to debt associated with our real estate investments. The increase in the balance since March 31, 2018 is related to debt of our foreign affiliates associated with purchases of equipment and buildings.