Debt - Schedule of Repurchase Transactions and Facilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Amount of Collateral	$ 580,167	$ 745,211
Master Repurchase Agreement
Debt Instrument [Line Items]
Maximum Borrowing Capacity	918,521	886,134
Amount Outstanding	414,114	534,089
Amount of Collateral	$ 580,167	$ 745,211
Percentage of Collateral Coverage	140.00%	140.00%
Interest rate	3.77%	4.80%
Master Repurchase Agreement | January 11, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 8,956
Amount Outstanding		8,956
Amount of Collateral		$ 12,834
Percentage of Collateral Coverage		143.00%
Interest rate		4.41%
Master Repurchase Agreement | February 1, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 13,322
Amount Outstanding		13,322
Amount of Collateral		$ 17,174
Percentage of Collateral Coverage		129.00%
Interest rate		4.53%
Master Repurchase Agreement | March 25, 2019 | Class A Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 6,396
Amount Outstanding		6,396
Amount of Collateral		$ 8,376
Percentage of Collateral Coverage		131.00%
Interest rate		4.34%
Master Repurchase Agreement | March 25, 2019 | Class B Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 7,020
Amount Outstanding		7,020
Amount of Collateral		$ 10,024
Percentage of Collateral Coverage		143.00%
Interest rate		4.49%
Master Repurchase Agreement | March 28, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 12,539
Amount Outstanding		12,539
Amount of Collateral		$ 15,846
Percentage of Collateral Coverage		126.00%
Interest rate		4.40%
Master Repurchase Agreement | April 25, 2019 | Class A Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 5,865
Amount Outstanding		5,865
Amount of Collateral		$ 7,580
Percentage of Collateral Coverage		129.00%
Interest rate		4.65%
Master Repurchase Agreement | April 25, 2019 | Class B-1 Certificates
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 10,549
Amount Outstanding		10,549
Amount of Collateral		$ 15,145
Percentage of Collateral Coverage		144.00%
Interest rate		4.85%
Master Repurchase Agreement | May 8, 2019 | 2017-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 10,933
Amount Outstanding		10,933
Amount of Collateral		$ 15,618
Percentage of Collateral Coverage		143.00%
Interest rate		4.84%
Master Repurchase Agreement | May 8, 2019 | Class B Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 18,226
Amount Outstanding		18,226
Amount of Collateral		$ 26,036
Percentage of Collateral Coverage		143.00%
Interest rate		4.74%
Master Repurchase Agreement | June 6, 2019 | Class A Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 44,224
Amount Outstanding		44,224
Amount of Collateral		$ 58,965
Percentage of Collateral Coverage		133.00%
Interest rate		4.65%
Master Repurchase Agreement | June 6, 2019 | Class B Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 3,786
Amount Outstanding		3,786
Amount of Collateral		$ 5,408
Percentage of Collateral Coverage		143.00%
Interest rate		4.80%
Master Repurchase Agreement | June 7, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 50,294
Amount Outstanding		50,294
Amount of Collateral		$ 66,747
Percentage of Collateral Coverage		133.00%
Interest rate		4.47%
Master Repurchase Agreement | June 21, 2019 | Class A Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 32,393
Amount Outstanding		32,393
Amount of Collateral		$ 43,390
Percentage of Collateral Coverage		134.00%
Interest rate		4.62%
Master Repurchase Agreement | June 21, 2019 | Class B Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 2,771
Amount Outstanding		2,771
Amount of Collateral		$ 4,050
Percentage of Collateral Coverage		146.00%
Interest rate		4.77%
Master Repurchase Agreement | June 28, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 8,860
Amount Outstanding		8,860
Amount of Collateral		$ 13,275
Percentage of Collateral Coverage		150.00%
Interest rate		4.64%
Master Repurchase Agreement | July 12 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 250,000
Amount Outstanding		195,644
Amount of Collateral		$ 289,908
Percentage of Collateral Coverage		148.00%
Interest rate		5.00%
Master Repurchase Agreement | September 24, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 400,000
Amount Outstanding		102,311
Amount of Collateral		$ 134,835
Percentage of Collateral Coverage		132.00%
Interest rate		4.89%
Master Repurchase Agreement | January 3, 2020 | Ajax Mortgage Loan Trust 2019-A
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 11,966
Amount Outstanding	11,966
Amount of Collateral	$ 15,742
Percentage of Collateral Coverage	132.00%
Interest rate	3.45%
Master Repurchase Agreement | January 3, 2020 | Ajax Mortgage Loan Trust 2019-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 4,096
Amount Outstanding	4,096
Amount of Collateral	$ 5,261
Percentage of Collateral Coverage	128.00%
Interest rate	3.45%
Master Repurchase Agreement | January 3, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2019-A
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 10,648
Amount Outstanding	10,648
Amount of Collateral	$ 14,058
Percentage of Collateral Coverage	132.00%
Interest rate	3.45%
Master Repurchase Agreement | January 3, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2019-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 1,644
Amount Outstanding	1,644
Amount of Collateral	$ 2,388
Percentage of Collateral Coverage	145.00%
Interest rate	3.55%
Master Repurchase Agreement | January 3, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2018-D
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 5,175
Amount Outstanding	5,175
Amount of Collateral	$ 6,855
Percentage of Collateral Coverage	132.00%
Interest rate	3.45%
Master Repurchase Agreement | January 3, 2020 | Class A Notes | 2018-A
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 6,093
Amount Outstanding	6,093
Amount of Collateral	$ 9,038
Percentage of Collateral Coverage	148.00%
Interest rate	3.45%
Master Repurchase Agreement | January 3, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2019-A
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 5,485
Amount Outstanding	5,485
Amount of Collateral	$ 7,050
Percentage of Collateral Coverage	129.00%
Interest rate	3.45%
Master Repurchase Agreement | January 3, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2019-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 1,576
Amount Outstanding	1,576
Amount of Collateral	$ 2,287
Percentage of Collateral Coverage	145.00%
Interest rate	3.55%
Master Repurchase Agreement | January 3, 2020 | Class B 1 Notes | Ajax Mortgage Loan Trust 2017-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 8,411
Amount Outstanding	8,411
Amount of Collateral	$ 11,098
Percentage of Collateral Coverage	132.00%
Interest rate	3.45%
Master Repurchase Agreement | January 10, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2019-G
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 21,088
Amount Outstanding	21,088
Amount of Collateral	$ 28,284
Percentage of Collateral Coverage	134.00%
Interest rate	3.47%
Master Repurchase Agreement | January 10, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2019-G
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 1,808
Amount Outstanding	1,808
Amount of Collateral	$ 2,640
Percentage of Collateral Coverage	146.00%
Interest rate	3.57%
Master Repurchase Agreement | January 13, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2017-C
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 8,956
Amount Outstanding	8,956
Amount of Collateral	$ 13,016
Percentage of Collateral Coverage	145.00%
Interest rate	4.16%
Master Repurchase Agreement | January 21, 2020 | Class A Notes
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 10,305
Amount Outstanding	10,305
Amount of Collateral	$ 13,521
Percentage of Collateral Coverage	131.00%
Interest rate	3.41%
Master Repurchase Agreement | January 21, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2018-G
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 15,718
Amount Outstanding	15,718
Amount of Collateral	$ 20,623
Percentage of Collateral Coverage	131.00%
Interest rate	3.41%
Master Repurchase Agreement | January 21, 2020 | Class A Notes | 2018-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 2,784
Amount Outstanding	2,784
Amount of Collateral	$ 4,050
Percentage of Collateral Coverage	145.00%
Interest rate	3.51%
Master Repurchase Agreement | January 21, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2018-G
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 5,840
Amount Outstanding	5,840
Amount of Collateral	$ 7,324
Percentage of Collateral Coverage	125.00%
Interest rate	3.41%
Master Repurchase Agreement | January 28, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2019-E
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 2,520
Amount Outstanding	2,520
Amount of Collateral	$ 3,381
Percentage of Collateral Coverage	134.00%
Interest rate	2.99%
Master Repurchase Agreement | January 28, 2020 | Class B 2 Notes | Ajax Mortgage Loan Trust 2017-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 5,318
Amount Outstanding	5,318
Amount of Collateral	$ 7,464
Percentage of Collateral Coverage	140.00%
Interest rate	3.19%
Master Repurchase Agreement | February 3, 2020 | Class M1 Notes | Ajax Mortgage Loan Trust 2017-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 7,568
Amount Outstanding	7,568
Amount of Collateral	$ 9,702
Percentage of Collateral Coverage	128.00%
Interest rate	4.19%
Master Repurchase Agreement | February 3, 2020 | Class M2 Notes | Ajax Mortgage Loan Trust 2017-B
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 6,664
Amount Outstanding	6,664
Amount of Collateral	$ 9,537
Percentage of Collateral Coverage	143.00%
Interest rate	4.19%
Master Repurchase Agreement | February 24, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2017-D
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 41,412
Amount Outstanding	41,412
Amount of Collateral	$ 54,828
Percentage of Collateral Coverage	132.00%
Interest rate	2.92%
Master Repurchase Agreement | March 25, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2018-C
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 7,075
Amount Outstanding	7,075
Amount of Collateral	$ 10,024
Percentage of Collateral Coverage	142.00%
Interest rate	3.96%
Master Repurchase Agreement | March 25, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2018-C
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 5,851
Amount Outstanding	5,851
Amount of Collateral	$ 7,423
Percentage of Collateral Coverage	127.00%
Interest rate	3.81%
Master Repurchase Agreement | March 26, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2019-E
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 27,075
Amount Outstanding	27,075
Amount of Collateral	$ 34,591
Percentage of Collateral Coverage	128.00%
Interest rate	3.81%
Master Repurchase Agreement | March 27, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2018-D
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 2,915
Amount Outstanding	2,915
Amount of Collateral	$ 3,709
Percentage of Collateral Coverage	127.00%
Interest rate	3.79%
Master Repurchase Agreement | June 3, 2020
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 1,132
Amount of Collateral	$ 1,607
Percentage of Collateral Coverage	142.00%
Interest rate	3.79%
Master Repurchase Agreement | June 3, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2017-D
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 6,097
Amount Outstanding	6,097
Amount of Collateral	$ 7,891
Percentage of Collateral Coverage	129.00%
Interest rate	3.64%
Master Repurchase Agreement | June 3, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2018-F
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 2,332
Amount Outstanding	2,332
Amount of Collateral	$ 3,360
Percentage of Collateral Coverage	144.00%
Interest rate	3.79%
Master Repurchase Agreement | June 3, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2018-E
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 4,704
Amount Outstanding	4,704
Amount of Collateral	$ 6,106
Percentage of Collateral Coverage	130.00%
Interest rate	3.64%
Master Repurchase Agreement | June 3, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2018-F
Debt Instrument [Line Items]
Amount Outstanding	$ 1,132
Master Repurchase Agreement | June 3, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2018-E
Debt Instrument [Line Items]
Maximum Borrowing Capacity	3,053
Amount Outstanding	3,053
Amount of Collateral	$ 4,035
Percentage of Collateral Coverage	132.00%
Interest rate	3.64%
Master Repurchase Agreement | June 19, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2019-H
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 13,447
Amount Outstanding	13,447
Amount of Collateral	$ 18,076
Percentage of Collateral Coverage	134.00%
Interest rate	3.55%
Master Repurchase Agreement | June 19, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2019-H
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 1,155
Amount Outstanding	1,155
Amount of Collateral	$ 1,687
Percentage of Collateral Coverage	146.00%
Interest rate	3.70%
Master Repurchase Agreement | June 30, 2020 | Class A Notes | Ajax Mortgage Loan Trust 2019-C
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 5,286
Amount Outstanding	5,286
Amount of Collateral	$ 7,044
Percentage of Collateral Coverage	133.00%
Interest rate	3.57%
Master Repurchase Agreement | June 30, 2020 | Class B Notes | Ajax Mortgage Loan Trust 2019-C
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 3,324
Amount Outstanding	3,324
Amount of Collateral	$ 4,667
Percentage of Collateral Coverage	140.00%
Interest rate	3.72%
Master Repurchase Agreement | July 10, 2020
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 250,000
Amount Outstanding	28,931
Amount of Collateral	$ 57,397
Percentage of Collateral Coverage	198.00%
Interest rate	4.28%
Master Repurchase Agreement | September 24, 2020
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 400,000
Amount Outstanding	116,662
Amount of Collateral	$ 164,403
Percentage of Collateral Coverage	141.00%
Interest rate	4.24%