Guarantees and Contingencies - Additional Information (Detail)	9 Months Ended	0 Months Ended	9 Months Ended
	Sep. 30, 2014 New Tricare South Region Contract	Jun. 26, 2013 Puerto Rico Health Insurance Administration Contracts East Southeast And Southwest Regions	Sep. 30, 2014 Military Services	Sep. 30, 2014 Medicare	Sep. 30, 2014 Medicaid
Loss Contingencies [Line Items]
Percentage of premiums and services revenue			1.00%	73.00%	2.00%
Contract term, years	5 years	3 years
Contract expiration date	Mar. 31, 2017	Jun. 30, 2013