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Fair Value Measurements (Tables) | 12 Months Ended
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Dec. 31, 2017
Fair Value Disclosures [Abstract] |
Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments |
|  | December 31, 2017 |  | December 31, 2016
($ in thousands) |  | Carrying Amount |  | Fair Value |  | Carrying Amount |  | Fair Value
Financial Assets |  |  |  |  |  |  |  |  |  |  |  |
Fixed income securities: |  |  |  |  |  |  |  |  |  |  |  |
HTM |  | $ | 42,129 |  |  | 44,100 |  |  | 101,556 |  |  | 105,211 |
AFS |  | 5,162,522 |  |  | 5,162,522 |  |  | 4,792,540 |  |  | 4,792,540 |
Equity securities, AFS |  | 182,705 |  |  | 182,705 |  |  | 146,753 |  |  | 146,753 |
Short-term investments |  | 165,555 |  |  | 165,555 |  |  | 221,701 |  |  | 221,701 |
Long-term debt: |  |  |  |  |  |  |  |
7.25% Senior Notes |  | 49,904 |  |  | 61,391 |  |  | 49,901 |  |  | 56,148 |
6.70% Senior Notes |  | 99,446 |  |  | 116,597 |  |  | 99,430 |  |  | 108,333 |
5.875% Senior Notes |  | 185,000 |  |  | 186,332 |  |  | 185,000 |  |  | 176,860 |
1.61% Borrowings from FHLBNY |  | 25,000 |  |  | 24,270 |  |  | 25,000 |  |  | 24,286 |
1.56% Borrowings from FHLBNY |  | 25,000 |  |  | 24,210 |  |  | 25,000 |  |  | 24,219 |
3.03% Borrowings from FHLBI |  | 60,000 |  |  | 60,334 |  |  | 60,000 |  |  | 59,313 |
Subtotal long-term debt |  | 444,350 |  |  | 473,134 |  |  | 444,331 |  |  | 449,159 |
Unamortized debt issuance costs |  | (5,234 | ) |  |  |  | (5,664 | ) |  |
Total long-term debt |  | $ | 439,116 |  |  |  |  |  | 438,667 |  |  |  |
Schedule of Quantitative Disclosures of our Financial Assets that were Measured at Fair Value |
December 31, 2017 |  |  |  | Fair Value Measurements Using
($ in thousands) |  | Assets Measured at Fair Value |  | Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1)1 |  | Significant Other Observable Inputs (Level 2)1 |  | Significant Unobservable Inputs (Level 3)
Description |  |  |  |  |  |  |  |  |  |  |  |
Measured on a recurring basis: |  |  |  |  |  |  |  |  |  |  |  |
AFS fixed income securities: |  |  |  |  |  |  |  |
U.S. government and government agencies |  | $ | 49,740 |  |  | 24,652 |  |  | 25,088 |  |  | — |
Foreign government |  | 18,555 |  |  | — |  |  | 18,555 |  |  | — |
Obligations of states and political subdivisions |  | 1,582,970 |  |  | — |  |  | 1,582,970 |  |  | — |
Corporate securities |  | 1,617,468 |  |  | — |  |  | 1,617,468 |  |  | — |
CLO and other ABS |  | 795,458 |  |  | — |  |  | 795,458 |  |  | — |
CMBS |  | 383,449 |  |  | — |  |  | 376,895 |  |  | 6,554 |
RMBS |  | 714,882 |  |  | — |  |  | 714,882 |  |  | — |
Total AFS fixed income securities |  | 5,162,522 |  |  | 24,652 |  |  | 5,131,316 |  |  | 6,554 |
AFS equity securities: |  |  |  |  |  |  |  |
Common stock 2 |  | 167,757 |  |  | 138,640 |  |  | — |  |  | 5,398 |
Preferred stock |  | 14,948 |  |  | 14,948 |  |  | — |  |  | — |
Total AFS equity securities |  | 182,705 |  |  | 153,588 |  |  | — |  |  | 5,398 |
Total AFS securities |  | 5,345,227 |  |  | 178,240 |  |  | 5,131,316 |  |  | 11,952 |
Short-term investments |  | 165,555 |  |  | 165,555 |  |  | — |  |  | — |
Total assets measured at fair value |  | $ | 5,510,782 |  |  | 343,795 |  |  | 5,131,316 |  |  | 11,952 |
December 31, 2016 |  |  |  | Fair Value Measurements Using
($ in thousands) |  | Assets Measured at Fair Value |  | Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1)1 |  | Significant Other Observable Inputs (Level 2)1 |  | Significant Unobservable Inputs (Level 3)
Description |  |  |  |  |  |  |  |  |  |  |  |
Measured on a recurring basis: |  |  |  |  |  |  |  |  |  |  |  |
AFS fixed income securities: |  |  |  |  |  |  |  |
U.S. government and government agencies |  | $ | 77,333 |  |  | 27,520 |  |  | 49,813 |  |  | — |
Foreign government |  | 26,865 |  |  | — |  |  | 26,865 |  |  | — |
Obligations of states and political subdivisions |  | 1,379,593 |  |  | — |  |  | 1,379,593 |  |  | — |
Corporate securities |  | 1,997,753 |  |  | — |  |  | 1,997,753 |  |  | — |
CLO and other ABS |  | 528,960 |  |  | — |  |  | 528,960 |  |  | — |
CMBS |  | 256,842 |  |  | — |  |  | 256,842 |  |  | — |
RMBS |  | 525,194 |  |  | — |  |  | 525,194 |  |  | — |
Total AFS fixed income securities |  | 4,792,540 |  |  | 27,520 |  |  | 4,765,020 |  |  | — |
AFS equity securities: |  |  |  |  |  |  |  |
Common stock |  | 130,608 |  |  | 122,932 |  |  | — |  |  | 7,676 |
Preferred stock |  | 16,145 |  |  | 16,145 |  |  | — |  |  | — |
Total AFS equity securities |  | 146,753 |  |  | 139,077 |  |  | — |  |  | 7,676 |
Total AFS securities |  | 4,939,293 |  |  | 166,597 |  |  | 4,765,020 |  |  | 7,676 |
Short-term investments |  | 221,701 |  |  | 221,701 |  |  | — |  |  | — |
Total assets measured at fair value |  | $ | 5,160,994 |  |  | 388,298 |  |  | 4,765,020 |  |  | 7,676 |
1 There were no transfers of securities between Level 1 and Level 2. 2 In accordance with ASU 2015-07, investments amounting to $23.7 million at December 31, 2017, respectively, were measured at fair value using the net asset value per share (or its practical expedient) and have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value.
Schedule of Summary of the Changes in Fair Value of Securities Using Level 3 Inputs |
2017 |  |  |  |
($ in thousands) |  | CMBS |  | Common Stock
Fair value, December 31, 2016 |  | $ | — |  |  | 7,676 |
Total net (losses) gains for the period included in: |  |  |  |  |
OCI |  | 4 |  |  | — |
Net income |  | — |  |  | — |
Purchases |  | 6,550 |  |  | 3,780 |
Sales |  | — |  |  | (3,958 | )
Issuances |  | — |  |  | — |
Settlements |  | — |  |  | — |
Transfers into Level 3 |  | — |  |  | — |
Transfers out of Level 3 |  | — |  |  | (2,100 | )
Fair value, December 31, 2017 |  | $ | 6,554 |  |  | $ | 5,398 |
Schedule of Quantitative Information of our Financial Assets and Liabilities that were Disclosed at Fair Value |
December 31, 2017 |  |  |  | Fair Value Measurements Using
($ in thousands) |  | Assets/Liabilities Disclosed at Fair Value |  | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) |  | Significant Other Observable Inputs (Level 2) |  | Significant Unobservable Inputs (Level 3)
Financial Assets |  |  |  |  |  |  |  |
HTM: |  |  |  |  |  |  |  |
Obligations of states and political subdivisions |  | $ | 26,261 |  |  | — |  |  | 26,261 |  |  | — |
Corporate securities |  | 17,839 |  |  | — |  |  | 12,306 |  |  | 5,533 |
Total HTM fixed income securities |  | $ | 44,100 |  |  | — |  |  | 38,567 |  |  | 5,533 |
Financial Liabilities |  |  |  |  |  |  |  |
Long-term debt: |  |  |  |  |  |  |  |
7.25% Senior Notes |  | $ | 61,391 |  |  | — |  |  | 61,391 |  |  | — |
6.70% Senior Notes |  | 116,597 |  |  | — |  |  | 116,597 |  |  | — |
5.875% Senior Notes |  | 186,332 |  |  | 186,332 |  |  | — |  |  | — |
1.61% Borrowings from FHLBNY |  | 24,270 |  |  | — |  |  | 24,270 |  |  | — |
1.56% Borrowings from FHLBNY |  | 24,210 |  |  | — |  |  | 24,210 |  |  | — |
3.03% Borrowings from FHLBI |  | 60,334 |  |  | — |  |  | 60,334 |  |  | — |
Total long-term debt |  | $ | 473,134 |  |  | 186,332 |  |  | 286,802 |  |  | — |
December 31, 2016 |  |  |  | Fair Value Measurements Using
($ in thousands) |  | Assets/Liabilities Disclosed at Fair Value |  | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) |  | Significant Other Observable Inputs (Level 2) |  | Significant Unobservable Inputs (Level 3)
Financial Assets |  |  |  |  |  |  |  |
HTM: |  |  |  |  |  |  |  |
Obligations of states and political subdivisions |  | $ | 79,916 |  |  | — |  |  | 79,916 |  |  | — |
Corporate securities |  | 24,075 |  |  | — |  |  | 16,565 |  |  | 7,510 |
CMBS |  | 1,220 |  |  | — |  |  | 1,220 |  |  | — |
Total HTM fixed income securities |  | $ | 105,211 |  |  | — |  |  | 97,701 |  |  | 7,510 |
Financial Liabilities |  |  |  |  |  |  |  |
Long-term debt: |  |  |  |  |  |  |  |
7.25% Senior Notes |  | $ | 56,148 |  |  | — |  |  | 56,148 |  |  | — |
6.70% Senior Notes |  | 108,333 |  |  | — |  |  | 108,333 |  |  | — |
5.875% Senior Notes |  | 176,860 |  |  | 176,860 |  |  | — |  |  | — |
1.61% Borrowings from FHLBNY |  | 24,286 |  |  | — |  |  | 24,286 |  |  | — |
1.56% Borrowings from FHLBNY |  | 24,219 |  |  | — |  |  | 24,219 |  |  | — |
3.03% Borrowings from FHLBI |  | 59,313 |  |  | — |  |  | 59,313 |  |  | — |
Total long-term debt |  | $ | 449,159 |  |  | 176,860 |  |  | 272,299 |  |  | — |

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- Definition Tabular disclosure of assets and liabilities that are disclosed at fair value. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References No definition available. + Details
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- Definition Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19279-110258 + Details
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