Equity-Based Compensation - Schedule of Activity Related to Stock Option Awards (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding, Beginning Balance | shares	3,441,900
Options, Forfeited | shares	(181,923)
Options, Expired | shares	(37,592)
Options, Exercised | shares	(590)
Options, Outstanding, Ending Balance | shares	3,221,795
Options, Exercisable at June 30, 2017 | shares	1,175,043
Weighted Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 18.67
Weighted Average Exercise Price, Forfeited | $ / shares	18.32
Weighted Average Exercise Price, Expired | $ / shares	18.84
Weighted Average Exercise Price, Exercised | $ / shares	18.67
Weighted Average Exercise Price, Outstanding, Ending Balance | $ / shares	18.69
Weighted Average Exercise Price, Exercisable at June 30, 2017 | $ / shares	$ 19.11
Weighted Average Remaining Contractual Life, Outstanding at June 30, 2017	8 years 2 months 1 day
Weighted Average Remaining Contractual Life, Exercisable at June 30, 2017	8 years 4 days
Aggregate Intrinsic Value, Outstanding at June 30, 2017 | $	$ 233
Aggregate Intrinsic Value, Exercisable at June 30, 2017 | $	$ 7