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
	Mar. 31, 2019	Mar. 31, 2018
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation (expense)	$ (1,890)	$ (2,077)
Income Taxes [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit	$ 454	$ 498