Offsetting Assets and Liabilities - Offsetting Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Offsetting Derivative Liabilities [Abstract]
Derivative instruments, at fair value, Gross Amounts Recognized Liabilities	$ 5,528	$ 1,581
Derivative instruments, at fair value, Gross Amounts Offset on the Balance Sheet	0	0
Derivative instruments, at fair value, Net Amount of Liabilities Presented on the Balance Sheet	5,528	1,581
Derivative instruments, at fair value, Gross Amounts Not Offset on Balance Sheet, Financial Instruments		0
Derivative instruments, at fair value, Gross Amounts Not Offset on the Balance Sheet, Cash Collateral Pledged	8,584	3,679
Derivative instruments, at fair value, Net Amount	0	0
Repurchase agreements - commercial mortgage loans
Offsetting Securities Sold under Agreements to Repurchase [Abstract]
Repurchase agreements, Gross Amounts of Recognized Liabilities	234,524	252,543
Repurchase agreements, Gross Amounts Offset on the Balance Sheet	0	0
Repurchase agreements, Net Amount of Liabilities Presented on the Balance Sheet	234,524	252,543
Repurchase agreements, Gross Amounts Not Offset on the Balance Sheet, Financial Instruments	370,760	394,229
Repurchase agreements, Gross Amounts Not Offset on the Balance Sheet, Cash Collateral Pledged	5,015	5,011
Repurchase agreements, Net Amount	0	0
Repurchase agreements - real estate securities
Offsetting Securities Sold under Agreements to Repurchase [Abstract]
Repurchase agreements, Gross Amounts of Recognized Liabilities	496,880	394,359
Repurchase agreements, Gross Amounts Offset on the Balance Sheet	0	0
Repurchase agreements, Net Amount of Liabilities Presented on the Balance Sheet	496,880	394,359
Repurchase agreements, Gross Amounts Not Offset on the Balance Sheet, Financial Instruments	609,776	455,301
Repurchase agreements, Gross Amounts Not Offset on the Balance Sheet, Cash Collateral Pledged	76,157	1,657
Repurchase agreements, Net Amount	$ 0	$ 0

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount, after effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price offset against a right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase.

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