Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Estimated Allowance and Liability for Appeals - RAC Contract
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 18,625	$ 16,443	$ 5,577
Additions Charged against Revenue	2,109	8,624	12,791
Appeals found in Providers Favor	(1,616)	(6,442)	(1,925)
Balance at End of Period	19,118	18,625	16,443
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	32	32	65
Additions Charged against Revenue	354	0	0
Recoveries	0	0	2
Charge-offs	0	0	(35)
Balance at End of Period	$ 386	$ 32	$ 32