Income Taxes - Schedule of Effective Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Computed “expected” tax provision (benefit)	$ 4,500	$ 90,300	$ 11,700
Change in income tax resulting from:
State taxes, net of federal benefit	1,500	8,500	1,400
Change in fair value of earnout	400
Non-deductible executive compensation	300	700
Change in federal tax rate		(17,300)
Change in state tax rate	500
Stock compensation	500	(1,000)
Change in unrecognized tax benefits	(300)
Other	500	1,400
Total provision (benefit) for taxes	$ 7,877	$ 82,612	$ 13,121