Acquisitions - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combinations [Abstract]
Revenues	$ 2,158,243	$ 2,049,658	$ 1,406,580
Net income (loss) attributable to the Company's common stockholders	$ (79,079)	$ 43,453	$ (157,524)
Basic net income (loss) per share attributable to common stockholders (in dollars per share)	$ (2.04)	$ 1.06	$ (3.50)