Legal and Regulatory Proceedings - Additional Information (Details)	3 Months Ended				12 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) Plaintiffs LegalMatter	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Loss Contingencies [Line Items]
Loss contingency reserve		$ 2,000,000		$ 95,000,000
Loss contingency accrual, provision		5,500,000	$ 30,000,000
Provision (benefit) for income taxes		$ 47,000,000			$ (42,797,000)	$ 462,000	$ (10,493,000)
Loss Contingency, Range of Possible Loss, Minimum				95,000,000
Loss Contingency, Range of Possible Loss, Maximum				$ 125,000,000
Number of plaintiffs | Plaintiffs					4
Number of lawsuits | LegalMatter					186
RehabCare
Loss Contingencies [Line Items]
Loss contingency reserve					$ 6,500,000
Scenario, Forecast [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	$ 125,000,000
Litigation settlement interest rate	1.875%