Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands		3 Months Ended
	Jan. 02, 2018 USD ($)	Mar. 31, 2019 USD ($) Practice_Groups	Mar. 31, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of practice groups | Practice_Groups		3
New accounting pronouncements or adoption of new standard resulted a (decrease) increase in net cash provided by investing activities		$ 9,736	$ 19,756
Accounting Standards Update 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
New accounting pronouncements or adoption of new standard resulted a (decrease) increase in net cash provided by investing activities			57,200
New accounting pronouncements or adoption of new standard resulted a (decrease) increase in cash, cash equivalents and restricted cash	$ 148,800		$ 91,600