Organization and Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 01, 2019	Mar. 31, 2019	Dec. 31, 2018
Organization And Summary Of Significant Accounting Policies [Line Items]
Right-of-use (ROU) assets		$ 49,304	$ 0
Operating lease liabilities		$ 70,414
ASU 2016-02 (Topic 842)
Organization And Summary Of Significant Accounting Policies [Line Items]
Right-of-use (ROU) assets	$ 50,000
Operating lease liabilities	70,900
Derecognition of deferred rent for certain lease incentives received	20,900
Recognition of Deferred Gain on Sale of Real Estate | ASU 2016-02 (Topic 842)
Organization And Summary Of Significant Accounting Policies [Line Items]
Deferred gain on sale of real estate as cumulative-effect adjustment to equity	$ 8,000