Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Taxes [Line Items]
Federal statutory rate	35.00%	35.00%	35.00%	35.00%
Income tax (benefit) expense	$ (13,705,000)	$ (134,781,000)	$ (187,231,000)	$ (174,390,000)
Memorial Business Combination Non Deductible Transaction Costs
Income Taxes [Line Items]
Income tax (benefit) expense	5,300,000
Equity Compensation
Income Taxes [Line Items]
Income tax (benefit) expense			3,700,000
Deferred compensation plan
Income Taxes [Line Items]
Income tax (benefit) expense	(682,000)	(2,600,000)	1,800,000	(3,500,000)
Valuation Allowance, Operating Loss Carryforwards | State
Income Taxes [Line Items]
Income tax (benefit) expense	$ 2,800,000	$ 8,500,000	$ 10,500,000	$ 19,800,000