The Company and Subsequent Events - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Company And Subsequent Events [Abstract]
Statutory Federal income tax rate	21.00%	35.00%
Tax cuts and jobs act of 2017, incomplete accounting, provisional income tax expense	$ 0	$ 20,153,000
Tax cuts and jobs act of 2017, incomplete accounting, change in tax rate, deferred tax balances, provisional income tax expense		5,808,000
Tax cuts and jobs act of 2017, incomplete accounting, provisional income tax expense related to onetime transition tax liability of foreign subsidiaries		23,923,000
Tax cuts and jobs act of 2017, incomplete accounting, benefit included in provision for income taxes to offset one-time transition tax related to previous deferred tax liability that existed for undistributed foreign earnings that were not permanently reinvested		$ 9,578,000