Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Taxes [Line Items]
Income tax (expense) benefit	$ 222,217	$ (14,600)	$ 219,839	$ (12,820)
Loss on extinguishment of Convertible Notes, tax benefit		$ 2,800		$ 2,800
Effective tax rate	35.50%	36.10%	35.50%	36.10%
Excess tax benefits from stock-based compensation			$ 13,444	$ 13,572
Contingent Consideration, Advisory Mergers and Acquisitions Fees [Member]
Income Taxes [Line Items]
Other tax expense (benefit)	$ (236,400)		(2,200)
Asset Impairment Adjustment [Member]
Income Taxes [Line Items]
Other tax expense (benefit)			$ 1,600