Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income tax expense (benefit)
Interest and penalties expense (benefit) relating to uncertain tax positions			$ (300)	$ (300)
Accrued interest and penalties relating to uncertain tax positions	$ 2,200		2,200		$ 2,500
Income taxes	32,208	$ 37,452	$ 100,489	$ 103,571
California Franchise Tax Board [Member]
Income tax expense (benefit)
Tax benefit	$ 1,100