Fair Value of Financial Instruments (Narrative) (Details) $ in Thousands	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Carrying value and estimated fair value of financial instruments
Real estate owned	$ 192,162	$ 182,940	$ 152,356	$ 104,443	$ 98,708	$ 80,503
Other real estate, fair value	$ 214,800		$ 175,800
Expected Dividend Rate | Minimum | Term notes backed by MSR related collateral
Carrying value and estimated fair value of financial instruments
Measurement input	0.056
Expected Dividend Rate | Maximum | Term notes backed by MSR related collateral
Carrying value and estimated fair value of financial instruments
Measurement input	0.068
Discount rate | Term notes backed by MSR related collateral
Carrying value and estimated fair value of financial instruments
Measurement input	0.0596