Schedule of Mortgage-Backed Securities (Details) - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Fair Value |
|
$ 1,242,266
|
$ 1,393,303
|
| Residential Mortgage Backed Securities [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
1,177,078
|
1,306,824
|
| Unamortized Premium (Discount) |
|
53,646
|
53,147
|
| Amortized Cost |
|
1,239,215
|
1,370,751
|
| Gross Unrealized Gain |
|
11,428
|
26,195
|
| Gross Unrealized Losses |
|
(8,377)
|
(3,643)
|
| Fair Value |
|
$ 1,242,266
|
$ 1,393,303
|
| Weighted Average Coupon |
|
3.97%
|
3.99%
|
| Weighted Average Yield |
|
3.39%
|
3.41%
|
| Weighted Average Life (Years) |
[1] |
7 years 26 days
|
7 years 164 days
|
| Non-Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 48,408
|
$ 50,668
|
| Unamortized Premium (Discount) |
|
(18,013)
|
(20,377)
|
| Amortized Cost |
|
30,395
|
30,291
|
| Gross Unrealized Gain |
|
2,264
|
2,896
|
| Gross Unrealized Losses |
|
(1,258)
|
(686)
|
| Fair Value |
|
$ 31,401
|
$ 32,501
|
| Weighted Average Coupon |
|
2.48%
|
2.29%
|
| Weighted Average Yield |
|
20.97%
|
10.76%
|
| Weighted Average Life (Years) |
[1] |
4 years 296 days
|
4 years 354 days
|
| 15-year fixed rate mortgages [Member] | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 162,546
|
$ 130,720
|
| Unamortized Premium (Discount) |
|
7,839
|
6,304
|
| Amortized Cost |
|
170,385
|
137,024
|
| Gross Unrealized Gain |
|
531
|
1,113
|
| Gross Unrealized Losses |
|
(655)
|
(109)
|
| Fair Value |
|
$ 170,261
|
$ 138,028
|
| Weighted Average Coupon |
|
3.38%
|
3.40%
|
| Weighted Average Yield |
|
2.31%
|
2.46%
|
| Weighted Average Life (Years) |
[1] |
4 years 361 days
|
5 years 157 days
|
| 20-year fixed rate mortgages [Member] | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 18,477
|
$ 9,764
|
| Unamortized Premium (Discount) |
|
1,277
|
577
|
| Amortized Cost |
|
19,754
|
10,341
|
| Gross Unrealized Gain |
|
153
|
227
|
| Gross Unrealized Losses |
|
(77)
|
0
|
| Fair Value |
|
$ 19,830
|
$ 10,568
|
| Weighted Average Coupon |
|
4.00%
|
4.00%
|
| Weighted Average Yield |
|
2.75%
|
3.04%
|
| Weighted Average Life (Years) |
[1] |
6 years 183 days
|
6 years 336 days
|
| 30-year fixed rate mortgages [Member] | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 842,524
|
$ 1,042,550
|
| Unamortized Premium (Discount) |
|
53,832
|
61,089
|
| Amortized Cost |
|
896,356
|
1,103,639
|
| Gross Unrealized Gain |
|
8,117
|
20,379
|
| Gross Unrealized Losses |
|
(3,679)
|
(1,764)
|
| Fair Value |
|
$ 900,794
|
$ 1,122,254
|
| Weighted Average Coupon |
|
4.12%
|
4.09%
|
| Weighted Average Yield |
|
3.11%
|
3.29%
|
| Weighted Average Life (Years) |
[1] |
8 years 106 days
|
8 years 175 days
|
| Adjustable Rate Mortgages | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 36,433
|
$ 41,710
|
| Unamortized Premium (Discount) |
|
2,196
|
2,813
|
| Amortized Cost |
|
38,629
|
44,523
|
| Gross Unrealized Gain |
|
81
|
90
|
| Gross Unrealized Losses |
|
(180)
|
(330)
|
| Fair Value |
|
$ 38,530
|
$ 44,283
|
| Weighted Average Coupon |
|
4.05%
|
4.60%
|
| Weighted Average Yield |
|
2.68%
|
3.08%
|
| Weighted Average Life (Years) |
[1] |
5 years 161 days
|
5 years 354 days
|
| Reverse mortgages [Member] | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 68,690
|
$ 31,412
|
| Unamortized Premium (Discount) |
|
6,515
|
2,741
|
| Amortized Cost |
|
75,205
|
34,153
|
| Gross Unrealized Gain |
|
34
|
300
|
| Gross Unrealized Losses |
|
(1,547)
|
(28)
|
| Fair Value |
|
$ 73,692
|
$ 34,425
|
| Weighted Average Coupon |
|
4.63%
|
4.91%
|
| Weighted Average Yield |
|
2.54%
|
2.56%
|
| Weighted Average Life (Years) |
[1] |
5 years 234 days
|
4 years 270 days
|
| Interest-Only [Member] | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Amortized Cost |
|
$ 8,491
|
$ 10,780
|
| Gross Unrealized Gain |
|
248
|
1,190
|
| Gross Unrealized Losses |
|
(981)
|
(726)
|
| Fair Value |
|
$ 7,758
|
$ 11,244
|
| Weighted Average Coupon |
|
3.82%
|
4.04%
|
| Weighted Average Yield |
|
3.30%
|
11.82%
|
| Weighted Average Life (Years) |
[1] |
2 years 131 days
|
2 years 248 days
|
| Agency Securities [Member] | Agency RMBS [Member] |
|
|
|
| Mortgage-Backed Securities [Line Items] |
|
|
|
| Current Principal |
|
$ 1,128,670
|
$ 1,256,156
|
| Unamortized Premium (Discount) |
|
71,659
|
73,524
|
| Amortized Cost |
|
1,208,820
|
1,340,460
|
| Gross Unrealized Gain |
|
9,164
|
23,299
|
| Gross Unrealized Losses |
|
(7,119)
|
(2,957)
|
| Fair Value |
|
$ 1,210,865
|
$ 1,360,802
|
| Weighted Average Coupon |
|
4.03%
|
4.05%
|
| Weighted Average Yield |
|
2.94%
|
3.24%
|
| Weighted Average Life (Years) |
[1] |
7 years 58 days
|
7 years 197 days
|
|
|