New Accounting Standards - Schedule of Impact of Adoption of New Lease Accounting Standard (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating lease liabilities	$ 56,631
Accounting Standards Update 2016-02
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating lease liabilities		$ 7,900