Supplemental Disclosure to Cash Flows - Summary of Supplemental Non-Cash and Other Cash Flow Information (Detail) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 172,250	$ 349,462	$ 75,105
Restricted cash	105	1,565	3,333
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	172,355	351,027	78,438	$ 43,968
Cash paid for income taxes, net of refunds	3,669	10,609	11,487
Non-cash transactions:
Contingent consideration related to business combinations	$ 0	$ 0	$ 1,007
Non-cash purchase consideration related to business combinations	0	12,508	0
Property and equipment purchases in accounts payable	$ 834	$ 501	$ 133
Commission payable converted to stock-based award	$ 314	$ 0	$ 0