Derivative Instruments - Summary of Fair Value of Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivative assets
Derivative instruments	$ 41,341	$ 48,186
Derivative liabilities
Total derivative instrument assets	41,341	48,186
Total derivative instrument liabilities	14,895	13,848
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative assets
Derivative instruments	12,733	6,046
Derivatives designated as hedging instruments: | Net investment cross currency swaps
Derivative liabilities
Derivative liability, noncurrent	6,642	1,451
Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative liabilities
Derivative liability, current	123	179
Derivatives not designated as hedging instruments: | Contingent redemption features - Series A Preferred Stock
Derivative assets
Derivative instruments	28,608	42,140
Derivatives not designated as hedging instruments: | Cross currency and interest rate swaps
Derivative liabilities
Derivative liability, current	0	4,279
Derivative liability, noncurrent	$ 8,130	$ 7,939