Interest rate of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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The gross carrying amount of the outstanding balance due under the mortgage loan.

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Amount of the contractual principal due as of the balance sheet date.

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Represents the weighted average duration of a group of mortgage loan receivables.

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Amount of financing receivable reclassified to held-for-sale.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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The percentage points (also referred to as 'margin') added to the reference rate as stated in the loan agreement and used to compute the variable rate on the loans receivable. For instance, the loan agreement might state that the interest rate the borrower is obligated to pay is the London Interbank Offered Rate (LIBOR) plus three quarters (3/4) of a percentage point adjusted quarterly (each three months). LIBOR in this example is the index or reference rate, 3/4 percentage point is the margin, the reference rate plus the margin is the fully indexed rate. This element would be used to report separately the margin.

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Amount of loan with variable or adjustable rate of interest.

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Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Loans - Held for Investment (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Investments in loans
Total gross loans	$ 11,761,182		$ 11,503,835
Total allowance	(97,312)		(33,611)
Carrying Value	11,663,870	$ 10,109,215	11,470,224	$ 9,794,254
Proceeds from borrowings	2,756,915	2,310,902
Payment of debt	1,923,754	1,778,819
Face Amount	11,820,754		11,530,915
Loans with variable rates of interest	$ 9,757,786
Weighted average spread of loans (as a percent)	4.10%
Period covered in data base	20 years
Total loans held-for-investment
Investments in loans
Total gross loans	$ 10,586,123		10,619,489
Total allowance	(97,187)		(33,415)
Face Amount	10,639,397		10,661,865
Loans held-for-sale
Investments in loans
Total gross loans	1,175,059		884,346
Carrying Value	1,174,934	1,144,490	884,150	1,187,552
Face Amount	1,181,357		869,050
Loans held-for-sale, residential
Investments in loans
Total gross loans	7,800
Commercial Portfolio Segment
Investments in loans
Total gross loans	8,913,961
Commercial Portfolio Segment \| Total loans held-for-investment
Investments in loans
Total gross loans	8,913,961		8,550,469
Total allowance	(81,054)		(33,415)
Carrying Value	8,832,907	7,514,628	8,517,054	7,075,577
Face Amount	8,946,589		8,590,776
Infrastructure Portfolio Segment
Investments in loans
Total gross loans	1,397,404
Infrastructure Portfolio Segment \| Total loans held-for-investment
Investments in loans
Total gross loans	1,397,404		1,397,448
Total allowance	(16,133)
Carrying Value	1,381,271	$ 1,450,097	1,397,448	1,456,779
Face Amount	$ 1,416,147		$ 1,416,164
Weighted Average Life	4 years 8 months 12 days		4 years 10 months 24 days
Infrastructure Portfolio Segment \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	5.00%		5.60%
Infrastructure Portfolio Segment \| Loans held-for-sale
Investments in loans
Total gross loans	$ 102,020		$ 119,724
Total allowance	(125)		(196)
Face Amount	$ 103,007		$ 121,271
Weighted Average Life	2 years 2 months 12 days		2 years 1 month 6 days
Infrastructure Portfolio Segment \| Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	2.90%		3.30%
Residential Portfolio Segment
Investments in loans
Total gross loans	$ 274,758
Residential Portfolio Segment \| Total loans held-for-investment
Investments in loans
Carrying Value	274,758		$ 671,572	$ 74,346
Residential Portfolio Segment \| Loans held-for-sale
Investments in loans
Reclassification to held-for-sale	422,700
RMBS, fair value option \| Loans held-for-sale
Investments in loans
Total gross loans			605,384
Face Amount			$ 587,144
Weighted Average Life			3 years 10 months 24 days
RMBS, fair value option \| Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)			6.20%
RMBS, fair value option \| Residential Portfolio Segment \| Loans held-for-sale
Investments in loans
Total gross loans	886,076
Face Amount	$ 892,815
Weighted Average Life	4 years 1 month 6 days
RMBS, fair value option \| Residential Portfolio Segment \| Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	6.10%
CMBS, fair value option \| Loans held-for-sale
Investments in loans
Total gross loans			$ 159,238
Face Amount			$ 160,635
Weighted Average Life			10 years
CMBS, fair value option \| Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)			3.90%
CMBS, fair value option \| Commercial Portfolio Segment \| Loans held-for-sale
Investments in loans
Total gross loans	$ 186,963
Face Amount	$ 185,535
Weighted Average Life	10 years
CMBS, fair value option \| Commercial Portfolio Segment \| Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	3.90%
First mortgage loan participation \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 8,290,772
Face Amount	$ 8,318,289
Weighted Average Life	1 year 10 months 24 days
First mortgage loan participation \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	5.30%
First mortgage loan participation \| Loans held-for-sale
Investments in loans
Total gross loans			$ 7,928,026
Face Amount			$ 7,962,788
Weighted Average Life			2 years
First mortgage loan participation \| Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)			5.80%
Infrastructure loans
Investments in loans
Loans with variable rates of interest	$ 1,397,404
Weighted average spread of loans (as a percent)	3.80%
Subordinated mortgages \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 68,230		$ 75,724
Face Amount	$ 69,485		$ 77,055
Weighted Average Life	3 years 6 months		3 years 4 months 24 days
Subordinated mortgages \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	8.80%		8.80%
Mezzanine Loans
Investments in loans
Carrying Value	$ 968,200		$ 967,000,000
Mezzanine Loans \| Total loans held-for-investment
Investments in loans
Total gross loans	523,901		484,164
Face Amount	$ 523,963		$ 484,408
Weighted Average Life	2 years		1 year 10 months 24 days
Mezzanine Loans \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	10.40%		11.00%
Residential loans, fair value option \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 274,758		$ 671,572
Face Amount	$ 276,661		$ 654,925
Weighted Average Life	4 years 1 month 6 days		3 years 9 months 18 days
Residential loans, fair value option \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	6.20%		6.10%
Other \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 31,058		$ 62,555
Face Amount	$ 34,852		$ 66,525
Weighted Average Life	2 years 2 months 12 days		1 year 7 months 6 days
Other \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	8.90%		8.20%