Servicing Rights Related Liabilities - Additional information (Details) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	May 31, 2016	Nov. 30, 2015	Jul. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Servicing Liabilities at Fair Value [Line Items]
Interest expense				$ 255,781	$ 273,606	$ 303,103
Excess Servicing Spread Liabilities [Member]
Servicing Liabilities at Fair Value [Line Items]
Interest expense					12,100	$ 9,000
Servicing Rights Financing [Member]
Servicing Liabilities at Fair Value [Line Items]
Interest expense				$ 4,200	$ 300
Excess Servicing Spread [Member]
Servicing Liabilities at Fair Value [Line Items]
Sales Price		$ 46,800	$ 75,400
Servicing Rights [Member]
Servicing Liabilities at Fair Value [Line Items]
Sales Price	$ 27,900	$ 17,800