Summary of Intangible Asset Account Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Total Intangible Assets [Abstract]
Beginning balance, intangible assets, gross	$ 769,851	$ 669,896
Finite-lived Intangible Assets Acquired	241,539	36,500
Effect of change in exchange rates	(18,883)	40,818
Ending balance, intangible assets, gross	992,507	747,214
Beginning balance, intangible liabilities, gross	0	0
Intangible liabilities acquired	(23,900)	0
Effect of change in exchange rates	0	0
Ending balance, intangible liabilities, gross	$ (23,900)	$ 0