Contingencies - Activity With Respect to Claims and Contingencies (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies, Balance at beginning of period	$ 126,978	$ 36,028
Payments, net	(203)	(192)
Payments on Behalf of Borrowers	(1,855)	0
Elimination of intercompany transactions	985	0
Additional accruals	(46,114)	0
Claims and contingencies, Balance at end of period	38,648	38,734
PEAKS Guarantee [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies, Balance at beginning of period	47,500
Additional accruals	0	0
Claims and contingencies, Balance at end of period	0	0
2009 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies, Balance at beginning of period	28,232
Additional accruals	3,803	3,054
Claims and contingencies, Balance at end of period	31,832	9,511
2007 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies, Balance at beginning of period	46,000
Payments, net	(46,000)	0
Additional accruals	0	0
Claims and contingencies, Balance at end of period	0	24,250
Other claims and contingencies [Member]
Schedule of Claims and Contingencies [Line Items]
Claims and contingencies, Balance at beginning of period	5,246
Additional accruals	1,570	(156)
Claims and contingencies, Balance at end of period	6,816	4,973
PEAKS Program Guarantee [Member]
Schedule of Claims and Contingencies [Line Items]
Payments, net	$ (516)	$ 0