Investment in Securities (Summary of Investment in Securities) (Details) - USD ($)
$ in Thousands |
12 Months Ended |
|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 1,408,233
|
$ 2,282,149
|
|
| Unamortized Premium (Discount) |
|
(196,118)
|
(150,821)
|
|
| Amortized Cost |
|
1,474,155
|
2,342,369
|
|
| Gross Unrealized Gains |
|
60,617
|
43,801
|
|
| Gross Unrealized Losses |
|
(59,229)
|
(9,638)
|
|
| Investment Owned At Fair Value, Net |
|
1,475,543
|
2,376,532
|
|
| Securities, at fair value(1)(2) |
[1],[2] |
1,514,185
|
2,449,941
|
|
| Securities sold short, at fair value |
|
$ (38,642)
|
$ (73,409)
|
$ (850,577)
|
| Fair Value |
|
|
|
$ 2,939,311
|
| Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.92%
|
4.23%
|
|
| Weighted Average Yield |
|
4.77%
|
4.01%
|
|
| Weighted average life |
|
4 years 5 months 26 days
|
5 years 10 months 24 days
|
|
| Long |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 1,446,237
|
$ 2,355,498
|
|
| Unamortized Premium (Discount) |
|
(199,280)
|
(151,329)
|
|
| Amortized Cost |
|
1,508,997
|
2,415,210
|
|
| Gross Unrealized Gains |
|
60,617
|
43,738
|
|
| Gross Unrealized Losses |
|
(55,429)
|
(9,007)
|
|
| Securities, at fair value(1)(2) |
|
$ 1,514,185
|
$ 2,449,941
|
|
| Long | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.84%
|
4.15%
|
|
| Weighted Average Yield |
|
4.88%
|
4.09%
|
|
| Weighted average life |
|
4 years 5 months 12 days
|
5 years 10 months 17 days
|
|
| Long | 15-year fixed-rate mortgages |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 67,875
|
$ 314,636
|
|
| Unamortized Premium (Discount) |
|
2,543
|
6,369
|
|
| Amortized Cost |
|
70,418
|
321,005
|
|
| Gross Unrealized Gains |
|
1,832
|
2,604
|
|
| Gross Unrealized Losses |
|
(36)
|
(203)
|
|
| Securities, at fair value(1)(2) |
|
$ 72,214
|
$ 323,406
|
|
| Long | 15-year fixed-rate mortgages | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.30%
|
3.05%
|
|
| Weighted Average Yield |
|
1.83%
|
2.28%
|
|
| Weighted average life |
|
3 years 2 months 26 days
|
3 years 18 days
|
|
| Long | 20-year fixed-rate mortgages |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 50,131
|
$ 804
|
|
| Unamortized Premium (Discount) |
|
3,097
|
49
|
|
| Amortized Cost |
|
53,228
|
853
|
|
| Gross Unrealized Gains |
|
182
|
24
|
|
| Gross Unrealized Losses |
|
0
|
0
|
|
| Securities, at fair value(1)(2) |
|
$ 53,410
|
$ 877
|
|
| Long | 20-year fixed-rate mortgages | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
2.57%
|
4.62%
|
|
| Weighted Average Yield |
|
1.08%
|
2.99%
|
|
| Weighted average life |
|
4 years 5 months 15 days
|
4 years 9 months 18 days
|
|
| Long | 30-year fixed-rate mortgages |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 626,021
|
$ 1,358,762
|
|
| Unamortized Premium (Discount) |
|
30,738
|
64,846
|
|
| Amortized Cost |
|
656,759
|
1,423,608
|
|
| Gross Unrealized Gains |
|
25,765
|
13,821
|
|
| Gross Unrealized Losses |
|
(444)
|
(2,830)
|
|
| Securities, at fair value(1)(2) |
|
$ 682,080
|
$ 1,434,599
|
|
| Long | 30-year fixed-rate mortgages | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.99%
|
4.20%
|
|
| Weighted Average Yield |
|
2.35%
|
2.95%
|
|
| Weighted average life |
|
4 years 2 months 1 day
|
6 years 7 months 17 days
|
|
| Long | Adjustable rate mortgages |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 6,171
|
$ 9,651
|
|
| Unamortized Premium (Discount) |
|
159
|
315
|
|
| Amortized Cost |
|
6,330
|
9,966
|
|
| Gross Unrealized Gains |
|
124
|
90
|
|
| Gross Unrealized Losses |
|
0
|
(54)
|
|
| Securities, at fair value(1)(2) |
|
$ 6,454
|
$ 10,002
|
|
| Long | Adjustable rate mortgages | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.66%
|
3.99%
|
|
| Weighted Average Yield |
|
2.27%
|
2.03%
|
|
| Weighted average life |
|
3 years 5 months 1 day
|
4 years 1 month 2 days
|
|
| Long | Reverse mortgages |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 89,383
|
$ 122,670
|
|
| Unamortized Premium (Discount) |
|
5,152
|
8,133
|
|
| Amortized Cost |
|
94,535
|
130,803
|
|
| Gross Unrealized Gains |
|
3,123
|
2,023
|
|
| Gross Unrealized Losses |
|
(29)
|
(26)
|
|
| Securities, at fair value(1)(2) |
|
$ 97,629
|
$ 132,800
|
|
| Long | Reverse mortgages | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.97%
|
4.43%
|
|
| Weighted Average Yield |
|
2.37%
|
2.78%
|
|
| Weighted average life |
|
4 years 7 months 6 days
|
6 years 8 months 1 day
|
|
| Long | Interest only securities |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Amortized Cost |
|
$ 43,406
|
$ 34,044
|
|
| Gross Unrealized Gains |
|
5,808
|
1,624
|
|
| Gross Unrealized Losses |
|
(1,558)
|
(389)
|
|
| Securities, at fair value(1)(2) |
|
$ 47,656
|
$ 35,279
|
|
| Long | Interest only securities | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.36%
|
2.81%
|
|
| Weighted Average Yield |
|
10.01%
|
9.27%
|
|
| Weighted average life |
|
4 years 10 months 6 days
|
3 years 10 months 9 days
|
|
| Long | Non-Agency RMBS |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 321,842
|
$ 274,353
|
|
| Unamortized Premium (Discount) |
|
(131,083)
|
(122,685)
|
|
| Amortized Cost |
|
190,759
|
151,668
|
|
| Gross Unrealized Gains |
|
15,880
|
12,549
|
|
| Gross Unrealized Losses |
|
(5,549)
|
(1,081)
|
|
| Securities, at fair value(1)(2) |
|
$ 201,090
|
$ 163,136
|
|
| Long | Non-Agency RMBS | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.15%
|
3.41%
|
|
| Weighted Average Yield |
|
6.40%
|
7.25%
|
|
| Weighted average life |
|
5 years 5 months 15 days
|
5 years 3 months 21 days
|
|
| Long | CMBS |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 188,085
|
$ 185,417
|
|
| Unamortized Premium (Discount) |
|
(61,763)
|
(67,961)
|
|
| Amortized Cost |
|
126,322
|
117,456
|
|
| Gross Unrealized Gains |
|
1,655
|
2,990
|
|
| Gross Unrealized Losses |
|
(16,910)
|
(480)
|
|
| Securities, at fair value(1)(2) |
|
$ 111,067
|
$ 119,966
|
|
| Long | CMBS | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
2.71%
|
3.31%
|
|
| Weighted Average Yield |
|
7.47%
|
6.62%
|
|
| Weighted average life |
|
8 years 1 month 2 days
|
8 years 11 months 8 days
|
|
| Long | Non-Agency IOs |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Amortized Cost |
|
$ 8,123
|
$ 6,517
|
|
| Gross Unrealized Gains |
|
1,792
|
1,817
|
|
| Gross Unrealized Losses |
|
(305)
|
(18)
|
|
| Securities, at fair value(1)(2) |
|
$ 9,610
|
$ 8,316
|
|
| Long | Non-Agency IOs | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
1.17%
|
1.10%
|
|
| Weighted Average Yield |
|
18.85%
|
8.18%
|
|
| Weighted average life |
|
3 years 5 months 26 days
|
4 years 1 month 20 days
|
|
| Long | CLOs |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Amortized Cost |
|
$ 208,907
|
$ 169,238
|
|
| Gross Unrealized Gains |
|
2,563
|
4,219
|
|
| Gross Unrealized Losses |
|
(30,199)
|
(3,014)
|
|
| Securities, at fair value(1)(2) |
|
$ 181,271
|
$ 170,443
|
|
| Long | CLOs | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
3.67%
|
5.05%
|
|
| Weighted Average Yield |
|
8.50%
|
9.62%
|
|
| Weighted average life |
|
3 years 6 months
|
4 years 9 months
|
|
| Long | Asset-backed securities, backed by consumer loans |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 69,646
|
$ 67,080
|
|
| Unamortized Premium (Discount) |
|
(24,936)
|
(19,154)
|
|
| Amortized Cost |
|
44,710
|
47,926
|
|
| Gross Unrealized Gains |
|
221
|
1,596
|
|
| Gross Unrealized Losses |
|
(6)
|
(912)
|
|
| Securities, at fair value(1)(2) |
|
$ 44,925
|
$ 48,610
|
|
| Long | Asset-backed securities, backed by consumer loans | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
11.95%
|
12.17%
|
|
| Weighted Average Yield |
|
18.57%
|
14.00%
|
|
| Weighted average life |
|
1 year 1 month 9 days
|
1 year 2 months 19 days
|
|
| Long | Corporate debt securities |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ 27,083
|
$ 22,125
|
|
| Unamortized Premium (Discount) |
|
(23,187)
|
(21,241)
|
|
| Amortized Cost |
|
3,896
|
884
|
|
| Gross Unrealized Gains |
|
1,296
|
229
|
|
| Gross Unrealized Losses |
|
(3)
|
0
|
|
| Securities, at fair value(1)(2) |
|
$ 5,189
|
$ 1,113
|
|
| Long | Corporate debt securities | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
2.13%
|
0.00%
|
|
| Weighted Average Yield |
|
6.75%
|
0.00%
|
|
| Weighted average life |
|
3 years 1 month 6 days
|
3 months 29 days
|
|
| Long | Corporate equity securities |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Amortized Cost |
|
$ 1,604
|
$ 1,242
|
|
| Securities, at fair value(1)(2) |
|
1,590
|
1,394
|
|
| Corporate equity, gross unrealized gains |
|
376
|
152
|
|
| Corporate equity, gross unrealized losses |
|
(390)
|
0
|
|
| Short |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
(38,004)
|
(73,349)
|
|
| Unamortized Premium (Discount) |
|
3,162
|
508
|
|
| Investment Sold, Not yet Purchased, Sale Proceeds |
|
(34,842)
|
(72,841)
|
|
| Gross Unrealized Gains |
|
0
|
63
|
|
| Gross Unrealized Losses |
|
(3,800)
|
(631)
|
|
| Securities sold short, at fair value |
|
$ (38,642)
|
$ (73,409)
|
|
| Short | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
0.26%
|
1.65%
|
|
| Weighted Average Yield |
|
0.09%
|
1.66%
|
|
| Weighted average life |
|
3 years 1 month 17 days
|
5 years 5 months 26 days
|
|
| Short | Corporate debt securities |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ (200)
|
$ (450)
|
|
| Unamortized Premium (Discount) |
|
(1)
|
(6)
|
|
| Investment Sold, Not yet Purchased, Sale Proceeds |
|
(201)
|
(456)
|
|
| Gross Unrealized Gains |
|
0
|
0
|
|
| Gross Unrealized Losses |
|
(17)
|
(15)
|
|
| Securities sold short, at fair value |
|
$ (218)
|
$ (471)
|
|
| Short | Corporate debt securities | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
5.09%
|
5.44%
|
|
| Weighted Average Yield |
|
4.67%
|
5.21%
|
|
| Weighted average life |
|
6 years 5 months 1 day
|
4 years 10 months 24 days
|
|
| Short | U.S. Treasury securities |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
|
$ (63,140)
|
|
| Unamortized Premium (Discount) |
|
|
381
|
|
| Investment Sold, Not yet Purchased, Sale Proceeds |
|
|
(62,759)
|
|
| Gross Unrealized Gains |
|
|
63
|
|
| Gross Unrealized Losses |
|
|
(298)
|
|
| Securities sold short, at fair value |
|
|
$ (62,994)
|
|
| Short | U.S. Treasury securities | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
|
1.76%
|
|
| Weighted Average Yield |
|
|
1.87%
|
|
| Weighted average life |
|
|
6 years 1 month 9 days
|
|
| Short | European sovereign bonds |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Current Principal |
|
$ (37,804)
|
$ (9,759)
|
|
| Unamortized Premium (Discount) |
|
3,163
|
133
|
|
| Investment Sold, Not yet Purchased, Sale Proceeds |
|
(34,641)
|
(9,626)
|
|
| Gross Unrealized Gains |
|
0
|
0
|
|
| Gross Unrealized Losses |
|
(3,783)
|
(318)
|
|
| Securities sold short, at fair value |
|
$ (38,424)
|
$ (9,944)
|
|
| Short | European sovereign bonds | Weighted Average |
|
|
|
|
| Securities, Available-for-sale [Line Items] |
|
|
|
|
| Weighted Average Coupon |
|
0.23%
|
0.77%
|
|
| Weighted Average Yield |
|
0.06%
|
0.12%
|
|
| Weighted average life |
|
3 years 1 month 9 days
|
1 year 6 months 29 days
|
|
|
|