Contingencies - Components of Recorded Liability Related to Claims and Contingencies (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 26, 2012	Dec. 31, 2011
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies	$ 38,952	$ 38,648	$ 126,978	$ 43,224	$ 38,734	$ 36,028
Other current liabilities	37,011		85,655	19,260
Other liabilities	1,941		41,323	23,964
Total	38,952	38,648	126,978	43,224	38,734	36,028
PEAKS Guarantee [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies	0		47,500	0
Total	0		47,500	0
2009 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies	31,982		28,232	13,028
Total	31,982		28,232	13,028
2007 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies	0		46,000	24,250
Total	0		46,000	24,250
Other claims and contingencies [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies	6,970		5,246	5,946
Total	$ 6,970		$ 5,246	$ 5,946