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v3.19.1

Investments (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 USD ($) security | Mar. 31, 2018 USD ($) | Dec. 31, 2018 USD ($) security
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | $ 5,229,535,000 |  | $ 5,196,784,000
Fair Value | 5,287,360,000 |  | 5,151,987,000
Other-than-temporary impairment losses | 0 |  | 0
Assets held by insurance regulators | 13,600,000 |  | $ 13,500,000
Proceeds from sales of fixed income securities | 106,000,000 | $ 10,800,000 |
Gross realized gains, fixed income securities | 700,000 | 100,000 |
Net impairment losses recognized in earnings | $ 100,000 | 0 |
Federal Home Loan Bank advances, collateral, value of principal, percent (as a percent) | 102.00% |  |
FHLB advance collateral | $ 171,600,000 |  |
Number of securities in unrealized loss position (in securities) | security | 420 |  | 721
Total fixed income securities |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | $ 5,229,535,000 |  | $ 5,196,784,000
Gross Unrealized Gains | 85,641,000 |  | 33,107,000
Gross Unrealized Losses | (27,816,000) |  | (77,904,000)
Fair Value | 5,287,360,000 |  | 5,151,987,000
Gross realized gain, fixed income securities | 1,300,000 | $ 300,000 |
U.S. Treasury securities and obligations of U.S. government corporations and agencies |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 167,821,000 |  | 167,655,000
Gross Unrealized Gains | 910,000 |  | 597,000
Gross Unrealized Losses | (589,000) |  | (1,076,000)
Fair Value | 168,142,000 |  | 167,176,000
Obligations of U.S. states and political subdivisions |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 1,611,092,000 |  | 1,701,826,000
Gross Unrealized Gains | 58,372,000 |  | 29,259,000
Gross Unrealized Losses | (2,226,000) |  | (10,985,000)
Fair Value | 1,667,238,000 |  | 1,720,100,000
Corporate debt securities |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 2,442,354,000 |  | 2,439,173,000
Gross Unrealized Gains | 23,363,000 |  | 2,103,000
Gross Unrealized Losses | (9,648,000) |  | (40,514,000)
Fair Value | 2,456,069,000 |  | 2,400,762,000
Asset backed securities (“ABS”) |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 217,469,000 |  | 111,953,000
Gross Unrealized Gains | 1,045,000 |  | 226,000
Gross Unrealized Losses | (33,000) |  | (146,000)
Fair Value | 218,481,000 |  | 112,033,000
Residential mortgage backed securities (“RMBS”) |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 188,201,000 |  | 189,238,000
Gross Unrealized Gains | 143,000 |  | 32,000
Gross Unrealized Losses | (7,859,000) |  | (10,309,000)
Fair Value | 180,485,000 |  | 178,961,000
Commercial mortgage backed securities (“CMBS”) |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 272,074,000 |  | 276,352,000
Gross Unrealized Gains | 1,808,000 |  | 888,000
Gross Unrealized Losses | (4,599,000) |  | (9,580,000)
Fair Value | 269,283,000 |  | 267,660,000
Collateralized loan obligations (“CLO”) |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Amortized Cost | 330,524,000 |  | 310,587,000
Gross Unrealized Gains | 0 |  | 2,000
Gross Unrealized Losses | (2,862,000) |  | (5,294,000)
Fair Value | $ 327,662,000 |  | $ 305,295,000

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