Contingencies - Activity With Respect to Claims and Contingencies (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies, beginning balance	$ 123,439	$ 36,028
Payments, net	(55,770)	(1,653)
Estimated recovery	803	0
Claims and contingencies, ending balance	81,235	44,247
PEAKS Program [Member]
Schedule of Claims and Contingencies [Line Items]
Additional reserves	721	0
Claims and contingencies, ending balance	40,000
2009 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Additional reserves	8,957	9,600
Claims and contingencies, ending balance	32,910
Other claims and contingencies [Member]
Schedule of Claims and Contingencies [Line Items]
Additional reserves	3,085	272
Claims and contingencies, ending balance	$ 8,325