Quantitative Information About Level 3 Fair Value Measurements - Prepayment Assumptions (Details) - Retained Interest [Member]	3 Months Ended
	Mar. 31, 2017
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Prepayment Method	Constant Prepayment Rate
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Prepayment Range	10.00%
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Prepayment Range	10.00%
Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Prepayment Range	10.00%