Stock-Based Compensation - Stock-Based Compensation Expense, Income Tax Benefits Related to Stock-Based Compensation and Excess Tax Benefits (Provision) Recorded by Company Both Plan and Non-Plan (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation (expense)	$ (2,200)	$ (1,673)	$ (4,090)	$ (3,750)
Income Taxes [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit	$ 528	$ 402	$ 982	$ 900