Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Change in uncertain tax positions	$ 0	$ 0	$ 300,000
Cash paid for income taxes, net of refunds	$ 60,300,000	46,700,000	29,300,000
Effective corporate federal tax rate	21.00%
Liability for uncertain tax positions	$ 3,000,000	$ 3,000,000	$ 0