Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	19.70%	25.60%
Favorable basis points on tax rate related to vesting and exercise of stock-based compensation awards, amount	$ 1,325,000
Favorable basis points on tax rate related to vesting and exercise of stock-based compensation awards	10.60%
Provision of Tax Cuts and Jobs Act, transition tax on undistributed foreign earnings, unfavorable impact, amount	$ 1,097,000
Provision of Tax Cuts and Jobs Act, transition tax on undistributed foreign earnings, unfavorable impact basis point on tax rate	8.80%
Federal statutory corporate income tax rate	21.00%		35.00%