Stockholders' Equity - Schedule of Net Transfers To/From Navient Subsidiary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions	$ 546,081	$ 188,792
Dividend	0	(120,000)
Corporate push-down	4,977	3,093
Net change in income tax accounts	15,659	(134,219)
Net change in receivable/payable	(87,277)	(101,044)
Other	(31)	0
Total net transfers (to)/from the entity that is now a subsidiary of Navient	479,409	(163,378)
Loan origination activities
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions	32,452	124,722
Loan sales
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions	45	35
Corporate overhead activities
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions	21,216	62,031
Special cash contribution
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions	472,718	0
Other
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions	$ 19,650	$ 2,004