Arrangements with Navient Corporation (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Apr. 30, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Income taxes payable, net	$ 283,118,000		$ 283,118,000		$ 283,000,000	$ 162,205,000
Deferred tax assets	238,000,000		238,000,000		310,000,000
Deferred tax asset discount	16,000,000		16,000,000		19,000,000
FDIC civil monetary penalties	3,300,000		3,300,000
Contingency refund	30,000,000		30,000,000
Minimum days past due that company may required spin-off company to purchase loans			90 days
Period of hardship forbearance			6 months
Private Education Loans Net	7,779,422,000		7,779,422,000			6,506,642,000
Interest income from related party	542,000	25,244,000	26,339,000	64,439,000
Gains on loans to related party	0	43,434,000	35,848,000	192,097,000
Write-down to fair value for loans sold to related party	4,571,000	15,632,000	51,001,000	48,260,000
Split Loans
Related Party Transaction [Line Items]
Private Education Loans Net	126,000,000		126,000,000
Non-Participated loans
Related Party Transaction [Line Items]
Loans sold to related party	$ 28,871,000	$ 571,946,000	$ 794,870,000	$ 2,281,404,000