Contingencies - Additional Information (Detail) $ in Thousands	1 Months Ended			3 Months Ended
	Mar. 31, 2017 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2012 Entity	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Other Commitments [Line Items]
Loss contingency liability						$ 69,300
Gain on litigation settlement				$ 526,827	$ 0
Dialysis businesses and other businesses
Other Commitments [Line Items]
Number of businesses acquired | Entity			2
Vainer Private Civil Suit
Other Commitments [Line Items]
Litigation settlement amount		$ (450,000)
Legal fees		$ 45,000
US Department Of Veterans Affairs Suit
Other Commitments [Line Items]
Litigation settlement amount	$ 538,000
Gain on litigation settlement	527,000
Noncontrolling Interest | US Department Of Veterans Affairs Suit
Other Commitments [Line Items]
Gain on litigation settlement	9,000
Operating Income (Loss) | US Department Of Veterans Affairs Suit
Other Commitments [Line Items]
Gain on litigation settlement	530,000
Equity Method Investments | Noncontrolling Interest | US Department Of Veterans Affairs Suit
Other Commitments [Line Items]
Gain on litigation settlement	$ 3,000