Commitments and Contingencies - Additional Information (Detail) £ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2016 GBP (£)	Dec. 31, 2011 USD ($) Hospital	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Nov. 30, 2010 USD ($)	Nov. 30, 2010 GBP (£)
Commitments and Contingencies Disclosure [Line Items]
Self-insured for professional and general liability	$ 210,000,000			$ 204,000,000
Self-insured for professional and general liability, current	48,000,000			48,000,000
Compensation liability claims	67,000,000			68,000,000
Compensation and related benefits	34,000,000			34,000,000
Accounts receivable, net	$ 1,374,737,000			1,302,429,000
Payment suspension period increased	180 days
Letters of Credit and Surety Bonds
Commitments and Contingencies Disclosure [Line Items]
Off-balance sheet contingent obligation	$ 129,000,000
Self Insurance Programs | Letters of Credit and Surety Bonds
Commitments and Contingencies Disclosure [Line Items]
Off-balance sheet contingent obligation	105,000,000
Other Debt Guarantees | Letters of Credit and Surety Bonds
Commitments and Contingencies Disclosure [Line Items]
Off-balance sheet contingent obligation	24,000,000
Location 1
Commitments and Contingencies Disclosure [Line Items]
Minimum Insurance Deductible	50,000
Location 2
Commitments and Contingencies Disclosure [Line Items]
Minimum Insurance Deductible	250,000
Illinois
Commitments and Contingencies Disclosure [Line Items]
Accounts receivable, net	16,000,000			28,000,000
Accounts receivable net greater than sixty days Past due	6,000,000			12,000,000
Texas
Commitments and Contingencies Disclosure [Line Items]
Accounts receivable	37,000,000			80,000,000
Texas | Uncompensated Care Program
Commitments and Contingencies Disclosure [Line Items]
Accounts receivable	31,000,000
Texas | Disproportionate Share Hospital Program
Commitments and Contingencies Disclosure [Line Items]
Accounts receivable	6,000,000
Earthquake
Commitments and Contingencies Disclosure [Line Items]
Minimum Insurance Deductible	250,000
Earthquake | PUERTO RICO
Commitments and Contingencies Disclosure [Line Items]
Commercial property insurance policies covering catastrophic losses	25,000,000
Maximum insurance deductible	25,000
Flood | Location 1
Commitments and Contingencies Disclosure [Line Items]
Maximum insurance deductible	500,000
Flood | Location 2
Commitments and Contingencies Disclosure [Line Items]
Maximum insurance deductible	250,000
Cygnet Health Care Limited
Commitments and Contingencies Disclosure [Line Items]
Property insurance | £		£ 180
Maximum | Wind Storms
Commitments and Contingencies Disclosure [Line Items]
Commercial property insurance policies covering catastrophic losses	$ 1,000,000,000
Percentage of insurance deductible	5.00%
Maximum | Earthquake
Commitments and Contingencies Disclosure [Line Items]
Commercial property insurance policies covering catastrophic losses	$ 250,000,000
Maximum | Earthquake | UNITED STATES
Commitments and Contingencies Disclosure [Line Items]
Commercial property insurance policies covering catastrophic losses	$ 100,000,000
Percentage of insurance deductible	5.00%
Minimum | Wind Storms
Commitments and Contingencies Disclosure [Line Items]
Percentage of insurance deductible	3.00%
Minimum | Earthquake | UNITED STATES
Commitments and Contingencies Disclosure [Line Items]
Percentage of insurance deductible	1.00%
Professional Liability | Cygnet Health Care Limited
Commitments and Contingencies Disclosure [Line Items]
Self-insured for professional and general liability | £								£ 10
General Liability | Cygnet Health Care Limited
Commitments and Contingencies Disclosure [Line Items]
Self-insured for professional and general liability | £								£ 25
Subsidiaries | Professional Liability | Maximum
Commitments and Contingencies Disclosure [Line Items]
Self-insured for professional and general liability							$ 10,000,000
Subsidiaries | General Liability | Maximum
Commitments and Contingencies Disclosure [Line Items]
Self-insured for professional and general liability							$ 3,000,000
Subsidiaries | General And Professional Liability Insurance Policies
Commitments and Contingencies Disclosure [Line Items]
Percentage of liability for claims paid under commercially insured coverage	10.00%
Subsidiaries | General And Professional Liability Insurance Policies | Maximum
Commitments and Contingencies Disclosure [Line Items]
Purchased several excess policies through commercial insurance carriers per occurrence				$ 250,000,000	$ 250,000,000	$ 200,000,000
Liability for claims paid under commercially insured coverage	$ 60,000,000
Subsidiaries | General And Professional Liability Insurance Policies | Minimum
Commitments and Contingencies Disclosure [Line Items]
Liability for claims paid under commercially insured coverage	$ 10,000,000
DPW
Commitments and Contingencies Disclosure [Line Items]
Repayment of legal settlement amount on demand			$ 4,000,000
Percentage of federal share on payments			55.00%
DPW | Pennsylvania
Commitments and Contingencies Disclosure [Line Items]
Number of behavioral health care hospitals | Hospital			7