Fair Value, Significant Unobservable Inputs Used in Fair Value Measurement (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Fair Value of Financial Assets [Abstract]
Percentage of revolving debt		90.00%
Level 3 [Member]
Valuation Technique and Input, Description [Abstract]
Fair Value		$ 294,907	$ 122,806
Level 3 [Member] | Discounted Cash Flow [Member] | MSRs Conventional [Member]
Valuation Technique and Input, Description [Abstract]
Fair Value		254,691	82,150
Annual cost to service, per loan	[1]	70	70
Level 3 [Member] | Discounted Cash Flow [Member] | MSRs Government [Member]
Valuation Technique and Input, Description [Abstract]
Fair Value		40,216	40,656
Annual cost to service, per loan	[1]	$ 111	$ 96
Level 3 [Member] | Discounted Cash Flow [Member] | Minimum [Member] | MSRs Conventional [Member]
Valuation Technique and Input, Description [Abstract]
Constant prepayment speed	[1]	4.50%	6.50%
Uncollected Payments	[1]	0.50%	0.20%
Level 3 [Member] | Discounted Cash Flow [Member] | Minimum [Member] | MSRs Government [Member]
Valuation Technique and Input, Description [Abstract]
Constant prepayment speed	[1]	6.30%	6.00%
Uncollected Payments	[1]	3.10%	0.40%
Level 3 [Member] | Discounted Cash Flow [Member] | Maximum [Member] | MSRs Conventional [Member]
Valuation Technique and Input, Description [Abstract]
Constant prepayment speed	[1]	20.60%	23.50%
Uncollected Payments	[1]	11.70%	1.80%
Level 3 [Member] | Discounted Cash Flow [Member] | Maximum [Member] | MSRs Government [Member]
Valuation Technique and Input, Description [Abstract]
Constant prepayment speed	[1]	17.90%	14.20%
Uncollected Payments	[1]	12.40%	5.20%
Level 3 [Member] | Discounted Cash Flow [Member] | Weighted Average [Member] | MSRs Conventional [Member]
Valuation Technique and Input, Description [Abstract]
Constant prepayment speed	[1]	9.10%	10.50%
Uncollected Payments	[1]	0.90%	0.80%
Discount rate	[1]	9.30%	9.30%
Level 3 [Member] | Discounted Cash Flow [Member] | Weighted Average [Member] | MSRs Government [Member]
Valuation Technique and Input, Description [Abstract]
Constant prepayment speed	[1]	8.90%	8.10%
Uncollected Payments	[1]	4.20%	3.30%
Discount rate	[1]	12.00%	12.00%

[1] Significant increases (decreases) in any of the inputs in isolation may result in significantly lower (higher) fair value measurements. A change in the assumption used for discount rates may be accompanied by a directionally similar change in the assumption used for the probability of uncollected payments and a directionally opposite change in the assumption used for prepayment rates.