Stock-Based Compensation - Stock-Based Compensation Expense, Income Tax Benefits Related to Stock-Based Compensation and Excess Tax Benefits (Provision) Recorded by Company (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation (expense)	$ (1,288)	$ (937)	$ (3,284)	$ (1,691)
Income Taxes [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit	$ 486	328	1,215	592
Additional Paid-in Capital [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit (deficiency) from stock-based compensation		$ (84)	$ 169	$ (30)