Mortgage Loans (Policies)	12 Months Ended
Dec. 31, 2018
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Abstract]
Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]	Loans Held for Investment When we acquire mortgage loans that we have the ability and the intent to hold for the foreseeable future or until maturity, we classify the loans as HFI. When we consolidate a securitization trust, we recognize the loans underlying the trust in our consolidated balance sheets. The trusts do not have the ability to sell mortgage loans and the use of such loans is limited exclusively to the settlement of obligations of the trusts. Therefore, mortgages acquired when we have the intent to securitize via trusts that are consolidated will generally be classified as HFI in our consolidated balance sheets both prior to and subsequent to their securitization. We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and allowance for loan losses. We recognize interest income on HFI loans on an accrual basis using the interest method over the contractual life of the loan, including the amortization of any deferred cost basis adjustments, such as the premium or discount at acquisition, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured.We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable.We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and an allowance for loan losses.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	Loans Held for Sale When we acquire mortgage loans that we intend to sell or securitize via trusts that will not be consolidated, we classify the loans as held for sale (“HFS”). We report the carrying value of HFS loans at the lower of cost or fair value. Any excess of an HFS loan’s cost over its fair value is recognized as a valuation allowance, with changes in the valuation allowance recognized as “Investment gains, net” in our consolidated statements of operations and comprehensive income. We recognize interest income on HFS loans on an accrual basis, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured. Purchased premiums, discounts and other cost basis adjustments on HFS loans are deferred upon loan acquisition, included in the cost basis of the loan, and not amortized. We determine any lower of cost or fair value adjustment on HFS loans at an individual loan level. In the event that we reclassify held for investment (“HFI”) loans to HFS loans, based upon a change in our intent, we record the loans at lower of cost or fair value on the date of redesignation. If the amounts charged off upon redesignation exceed the allowance related to the loans, we record a provision for credit losses. If the amounts charged off are less than the allowance related to the loans, we recognize a benefit for credit losses. We recognize recoveries of previously charged-off amounts as a reduction to charge-offs.We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in “Investment gains, net” in our consolidated statements of operations and comprehensive income.
Troubled Debt Restructurings [Policy Text Block]	Restructured Loans A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a troubled debt restructuring (“TDR”). Our loss mitigation programs primarily include modifications that result in the capitalization of past due amounts in combination with interest rate reductions and/or the extension of the loan’s maturity date. Such restructurings are granted to borrowers in financial difficulty on either a permanent or contingent basis, as in the case of modifications with a trial period. We consider these types of loan restructurings to be TDRs. We generally do not include principal or past due interest forgiveness as part of our loss mitigation programs, and, as a result, we generally do not charge off any outstanding principal or accrued interest amounts at the time of loan modification. We believe that the loan underwriting activities we perform as a part of our loan modification process coupled with the borrower’s successful performance during any required trial period provide us reasonable assurance regarding the collectibility of the principal and interest due in accordance with the loan’s modified terms, which include any past due interest amounts that are capitalized as principal at the time of modification. As such, the loan is returned to accrual status when the loan modification is completed (i.e., at the end of the trial period), and we accrue interest thereafter in accordance with our interest accrual policy. If the loan was on nonaccrual status prior to entering the trial period, it remains on nonaccrual status until the borrower demonstrates performance via the trial period and the modification is finalized. In addition to these loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans, forbearance arrangements, and the capitalization only of past due amounts. Repayment plans and forbearance arrangements are informal agreements with the borrower that do not result in the legal modification of the loan. For all of these activities, we consider the deferral or capitalization of three or fewer missed payments to represent only an insignificant delay, and thus not a TDR. If we defer or capitalize more than three missed payments, the delay is no longer considered insignificant, and the restructuring is accounted for as a TDR. We measure impairment of a loan restructured in a TDR individually based on the excess of the recorded investment in the loan over the present value of the expected future cash inflows discounted at the loan’s original effective interest rate. Costs incurred to complete a TDR are expensed as incurred. However, when foreclosure is probable on an individually impaired loan, we measure impairment based on the difference between our recorded investment in the loan and the fair value of the underlying property, adjusted for the estimated costs to sell the property and estimated insurance or other proceeds we expect to receive. A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a TDR. In addition to formal loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans and forbearance arrangements, both of which represent informal agreements with the borrower that do not result in the legal modification of the loan’s contractual terms. We account for these informal restructurings as a TDR if we defer more than three missed payments. We also classify loans to certain borrowers who have received bankruptcy relief as TDRs.

Mortgage Loans (Policies)

12 Months Ended

Dec. 31, 2018

SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Abstract]

Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]

Loans Held for Investment

When we acquire mortgage loans that we have the ability and the intent to hold for the foreseeable future or until maturity, we classify the loans as HFI. When we consolidate a securitization trust, we recognize the loans underlying the trust in our consolidated balance sheets. The trusts do not have the ability to sell mortgage loans and the use of such loans is limited exclusively to the settlement of obligations of the trusts. Therefore, mortgages acquired when we have the intent to securitize via trusts that are consolidated will generally be classified as HFI in our consolidated balance sheets both prior to and subsequent to their securitization.

We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and allowance for loan losses. We recognize interest income on HFI loans on an accrual basis using the interest method over the contractual life of the loan, including the amortization of any deferred cost basis adjustments, such as the premium or discount at acquisition, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured.We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable.We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and an allowance for loan losses.

Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]

Loans Held for Sale

When we acquire mortgage loans that we intend to sell or securitize via trusts that will not be consolidated, we classify the loans as held for sale (“HFS”). We report the carrying value of HFS loans at the lower of cost or fair value. Any excess of an HFS loan’s cost over its fair value is recognized as a valuation allowance, with changes in the valuation allowance recognized as “Investment gains, net” in our consolidated statements of operations and comprehensive income. We recognize interest income on HFS loans on an accrual basis, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured. Purchased premiums, discounts and other cost basis adjustments on HFS loans are deferred upon loan acquisition, included in the cost basis of the loan, and not amortized. We determine any lower of cost or fair value adjustment on HFS loans at an individual loan level.

In the event that we reclassify held for investment (“HFI”) loans to HFS loans, based upon a change in our intent, we record the loans at lower of cost or fair value on the date of redesignation. If the amounts charged off upon redesignation exceed the allowance related to the loans, we record a provision for credit losses. If the amounts charged off are less than the allowance related to the loans, we recognize a benefit for credit losses. We recognize recoveries of previously charged-off amounts as a reduction to charge-offs.We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in “Investment gains, net” in our consolidated statements of operations and comprehensive income.

Troubled Debt Restructurings [Policy Text Block]

Restructured Loans

A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a troubled debt restructuring (“TDR”). Our loss mitigation programs primarily include modifications that result in the capitalization of past due amounts in combination with interest rate reductions and/or the extension of the loan’s maturity date. Such restructurings are granted to borrowers in financial difficulty on either a permanent or contingent basis, as in the case of modifications with a trial period. We consider these types of loan restructurings to be TDRs.

We generally do not include principal or past due interest forgiveness as part of our loss mitigation programs, and, as a result, we generally do not charge off any outstanding principal or accrued interest amounts at the time of loan modification. We believe that the loan underwriting activities we perform as a part of our loan modification process coupled with the borrower’s

successful performance during any required trial period provide us reasonable assurance regarding the collectibility of the principal and interest due in accordance with the loan’s modified terms, which include any past due interest amounts that are capitalized as principal at the time of modification. As such, the loan is returned to accrual status when the loan modification is completed (i.e., at the end of the trial period), and we accrue interest thereafter in accordance with our interest accrual policy. If the loan was on nonaccrual status prior to entering the trial period, it remains on nonaccrual status until the borrower demonstrates performance via the trial period and the modification is finalized.

In addition to these loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans, forbearance arrangements, and the capitalization only of past due amounts. Repayment plans and forbearance arrangements are informal agreements with the borrower that do not result in the legal modification of the loan. For all of these activities, we consider the deferral or capitalization of three or fewer missed payments to represent only an insignificant delay, and thus not a TDR. If we defer or capitalize more than three missed payments, the delay is no longer considered insignificant, and the restructuring is accounted for as a TDR.

We measure impairment of a loan restructured in a TDR individually based on the excess of the recorded investment in the loan over the present value of the expected future cash inflows discounted at the loan’s original effective interest rate. Costs incurred to complete a TDR are expensed as incurred. However, when foreclosure is probable on an individually impaired loan, we measure impairment based on the difference between our recorded investment in the loan and the fair value of the underlying property, adjusted for the estimated costs to sell the property and estimated insurance or other proceeds we expect to receive. A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a TDR. In addition to formal loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans and forbearance arrangements, both of which represent informal agreements with the borrower that do not result in the legal modification of the loan’s contractual terms. We account for these informal restructurings as a TDR if we defer more than three missed payments. We also classify loans to certain borrowers who have received bankruptcy relief as TDRs.