Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Debt issuance costs	$ 6,627	$ 6,286
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares, outstanding (in shares)	38,837,749	38,553,413
Treasury stock, shares outstanding (in shares)	9,363,166	9,246,002