Recent Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 17,953	$ 18,651
Operating lease liabilities	$ 19,509	20,203
Cumulative adjustment for adoption of ASU 2016-01		125
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		18,700
Operating lease liabilities		$ 20,200