Arrangements with Navient Corporation (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
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	$ 9,701,152,000		$ 8,246,647,000
Interest income from related party	168,000	24,027,000
Gains on loans to related party	0	33,888,000
Write-down to fair value for loans sold to related party	2,181,000	28,963,000
Split Loans
Related Party Transaction [Line Items]
Private Education Loans Net	108,000,000
Participated loans [Member]
Related Party Transaction [Line Items]
Loans sold to related party	$ 8,714,000	$ 671,819,000