Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Accumulated amortization of debt financing costs	$ 2,409	$ 2,580
Class A common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Class A common stock, shares authorized	500,000,000	500,000,000
Class A common stock, shares outstanding	98,096,323	97,860,048
Treasury stock, shares	178,346	157,812