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Derivative Instruments - Summary of Fair Value of Derivative Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 23, 2018	Dec. 31, 2017
Assets
Derivative instruments	$ 682		$ 48,186
Liabilities
Total derivative instrument assets	682		48,186
Total derivative instrument liabilities	7,293		13,848
Derivatives designated as hedging instruments: \| Interest rate swaps
Assets
Derivative instruments	0		6,046
Derivatives designated as hedging instruments: \| Net investment cross currency swaps
Assets
Derivative instruments	682		0
Liabilities
Derivative liability, noncurrent	0		1,451
Derivatives not designated as hedging instruments: \| Interest rate swaps
Liabilities
Derivative liability, current	35		179
Derivatives not designated as hedging instruments: \| Contingent redemption features - Series A Preferred Stock
Assets
Derivative instruments	0	$ 140,300	42,140
Derivatives not designated as hedging instruments: \| Cross currency and interest rate swaps
Liabilities
Derivative liability, noncurrent	7,258		7,939
Derivative liability, current	$ 0		$ 4,279