Income Taxes - Summary of Differences In Effective Tax Rate and Federal Statutory Rate Due to State Income Taxes, Equity Compensation and Other Tax Items (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Total income before income taxes	$ 7,107	$ 91,914
U.S. federal statutory rate	21.00%	21.00%
Total tax expense at statutory rate	$ 1,492	$ 19,302
State and local income taxes, net of federal benefit	818	4,494
Equity compensation	3,391	664
Change in valuation allowances:
State net operating loss carryforwards & other	352	15,678
Other	231	1,381
Permanent differences and other	(596)	1,157
Total (benefit) expense for income taxes	$ 5,688	$ 42,676
Effective tax rate	80.00%	46.40%