Allowance for Loan Losses (Details 2) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Accrued Interest Receivable
Total Loan	$ 1,148,687	$ 1,270,876
Greater than 90 Days Past Due	51,309	54,914
Allowance for Uncollectible Interest	87,130	93,812
Private Education Loan - Traditional [Member]
Accrued Interest Receivable
Total Loan	970,674	1,062,289
Greater than 90 Days Past Due	33,319	34,644
Allowance for Uncollectible Interest	50,718	56,755
Private Education Loan Non - Traditional [Member]
Accrued Interest Receivable
Total Loan	178,013	208,587
Greater than 90 Days Past Due	17,990	20,270
Allowance for Uncollectible Interest	$ 36,412	$ 37,057