Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended			24 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Goodwill and Intangible Assets [Line Items]
Goodwill, impairment charge	$ 9,300	$ 0	$ 0	$ 9,313	$ 0
Fair value assets measured on non-recurring basis		950,717	979,105		950,717
Goodwill	$ 660,981	660,981	$ 660,981	$ 660,981	660,981
Fair Value Measurement Non-Recurring | Level 3
Goodwill and Intangible Assets [Line Items]
Fair value assets measured on non-recurring basis		692,600			692,600
Goodwill		661,000			661,000
Indefinite-lived intangible assets		$ 31,600			$ 31,600