Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2017	Jun. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	26.50%	22.00%
Favorable basis points on tax rate related to vesting and exercise of stock-based compensation awards, amount		$ 2,760,000
Favorable basis points on tax rate related to vesting and exercise of stock-based compensation awards		1.00%
Provision of Tax Cuts and Jobs Act, transition tax on undistributed foreign earnings, unfavorable impact, amount		$ 1,664,000
Provision of Tax Cuts and Jobs Act, transition tax on undistributed foreign earnings, unfavorable impact basis point on tax rate		0.60%
Provision of Tax Cuts and Jobs Act, nondeductible portion of transaction costs, unfavorable impact, amount		$ 2,369,000
Provision of Tax Cuts and Jobs Act, nondeductible portion of transaction costs, unfavorable impact, amount		0.90%
Federal statutory corporate income tax rate		21.00%	35.00%