Investments | Investments Fixed income securities The amortized cost, gross unrealized gains and losses, and fair value of investments in fixed income securities classified as available-for-sale at September 30, 2019 and December 31, 2018 are shown in tables 7.1a and 7.1b below. Details of fixed income securities by category as of September 30, 2019 Table 7.1a (In thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) (1) Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 197,748 $ 1,456 $ (75 ) $ 199,129 Obligations of U.S. states and political subdivisions 1,552,283 108,763 (494 ) 1,660,552 Corporate debt securities 2,653,124 74,630 (3,151 ) 2,724,603 Asset backed securities (“ABS”) 212,792 2,819 (65 ) 215,546 Residential mortgage backed securities (“RMBS”) 248,098 1,022 (2,663 ) 246,457 Commercial mortgage backed securities (“CMBS”) 280,364 6,714 (266 ) 286,812 Collateralized loan obligations (“CLOs”) 329,484 81 (1,672 ) 327,893 Total fixed income securities $ 5,473,893 $ 195,485 $ (8,386 ) $ 5,660,992 Details of fixed income securities by category as of December 31, 2018 Table 7.1b (In thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) (1) Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 167,655 $ 597 $ (1,076 ) $ 167,176 Obligations of U.S. states and political subdivisions 1,701,826 29,259 (10,985 ) 1,720,100 Corporate debt securities 2,439,173 2,103 (40,514 ) 2,400,762 ABS 111,953 226 (146 ) 112,033 RMBS 189,238 32 (10,309 ) 178,961 CMBS 276,352 888 (9,580 ) 267,660 CLOs 310,587 2 (5,294 ) 305,295 Total fixed income securities $ 5,196,784 $ 33,107 $ (77,904 ) $ 5,151,987 (1) At September 30, 2019 and December 31, 2018 , there were no other-than-temporary impairment losses recorded in other comprehensive income. The increase in gross unrealized gains and the decrease in gross unrealized losses in our fixed income securities from December 31, 2018 to September 30, 2019 were primarily caused by declines in interest rates during that period. We had $13.8 million and $13.5 million of investments at fair value on deposit with various states as of September 30, 2019 and December 31, 2018 , respectively, due to regulatory requirements of those state insurance departments. The amortized cost and fair values of fixed income securities at September 30, 2019 , by contractual maturity, are shown in table 7.2 below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most ABS, RMBS, CMBS, and CLOs provide for periodic payments throughout their lives, they are listed in separate categories. Fixed income securities maturity schedule Table 7.2 September 30, 2019 (In thousands) Amortized cost Fair Value Due in one year or less $ 372,478 $ 373,388 Due after one year through five years 1,928,972 1,966,387 Due after five years through ten years 1,001,486 1,059,774 Due after ten years 1,100,219 1,184,735 4,403,155 4,584,284 ABS 212,792 215,546 RMBS 248,098 246,457 CMBS 280,364 286,812 CLOs 329,484 327,893 Total as of September 30, 2019 $ 5,473,893 $ 5,660,992 Proceeds from sales of fixed income securities classified as available-for-sale were $201.4 million and $338.9 million during the nine months ended September 30, 2019 and 2018 , respectively. Gross gains of $3.3 million and $5.3 million and gross losses of $0.7 million and $3.0 million were realized on those sales during the three and nine months ended September 30, 2019 , respectively. Gross gains of $0.3 million and $0.4 million and gross losses of $2.3 million and $3.3 million were realized on those sales during the three and nine months ended September 30, 2018 , respectively. During the nine months ended September 30, 2019 , we recorded other-than-temporary impairment (“OTTI”) losses of $0.1 million . During the three and nine months ended September 30, 2018 , we recorded OTTI losses of $0.5 million and $1.8 million , respectively. Equity securities The cost and fair value of investments in equity securities at September 30, 2019 and December 31, 2018 are shown in tables 7.3a and 7.3b below. Details of equity security investments as of September 30, 2019 Table 7.3a (In thousands) Cost Gross Gains Gross Losses Fair Value Equity securities $ 17,205 $ 163 $ (8 ) $ 17,360 Details of equity security investments as of December 31, 2018 Table 7.3b (In thousands) Cost Gross Gains Gross Losses Fair Value Equity securities $ 3,993 $ 11 $ (72 ) $ 3,932 For the three and nine months ended September 30, 2019 , we recognized an insignificant amount and $0.2 million , respectively, of net gains on equity securities still held as of September 30, 2019 . For the nine months ended September 30, 2018 , we recognized $3.6 million of net gains on equity securities still held as of September 30, 2018 . Other invested assets Other invested assets include an investment in Federal Home Loan Bank (“FHLB”) stock that is carried at cost, which due to its nature approximates fair value. Ownership of FHLB stock provides access to a secured lending facility, and our current FHLB Advance amount is secured by eligible collateral whose fair value is maintained at a minimum of 102% of the outstanding principal balance. As of September 30, 2019 , that collateral consisted of fixed income securities included in our total investment portfolio, and cash and cash equivalents, with a total fair value of $165.4 million . Unrealized investment losses Tables 7.4a and 7.4b below summarize, for all available-for-sale investments in an unrealized loss position at September 30, 2019 and December 31, 2018 , the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in tables 7.4a and 7.4b are estimated using the process described in Note 8 - “Fair Value Measurements” to these consolidated financial statements and in Note 3 - “Significant Accounting Policies” of the notes to the consolidated financial statements in our 2018 Annual Report on Form 10-K. Unrealized loss aging for securities by type and length of time as of September 30, 2019 Table 7.4a Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 25,284 $ (48 ) $ 7,364 $ (27 ) $ 32,648 $ (75 ) Obligations of U.S. states and political subdivisions 4,965 (467 ) 10,007 (27 ) 14,972 (494 ) Corporate debt securities 135,541 (2,818 ) 78,842 (333 ) 214,383 (3,151 ) ABS 8,998 (65 ) — — 8,998 (65 ) RMBS 47,166 (309 ) 116,534 (2,354 ) 163,700 (2,663 ) CMBS 21,882 (196 ) 13,579 (70 ) 35,461 (266 ) CLOs 147,272 (1,008 ) 113,322 (664 ) 260,594 (1,672 ) Total $ 391,108 $ (4,911 ) $ 339,648 $ (3,475 ) $ 730,756 $ (8,386 ) Unrealized loss aging for securities by type and length of time as of December 31, 2018 Table 7.4b Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 23,710 $ (15 ) $ 69,146 $ (1,061 ) $ 92,856 $ (1,076 ) Obligations of U.S. states and political subdivisions 316,655 (3,875 ) 358,086 (7,110 ) 674,741 (10,985 ) Corporate debt securities 1,272,279 (18,130 ) 785,627 (22,384 ) 2,057,906 (40,514 ) ABS 51,324 (146 ) — — 51,324 (146 ) RMBS 24 — 178,573 (10,309 ) 178,597 (10,309 ) CMBS 65,704 (1,060 ) 163,272 (8,520 ) 228,976 (9,580 ) CLOs 296,497 (5,294 ) — — 296,497 (5,294 ) Total $ 2,026,193 $ (28,520 ) $ 1,554,704 $ (49,384 ) $ 3,580,897 $ (77,904 ) The unrealized losses in all categories of our investments at September 30, 2019 and December 31, 2018 were primarily caused by changes in interest rates between the time of purchase and the respective fair value measurement date. There were 183 and 721 securities in an unrealized loss position at September 30, 2019 and December 31, 2018 |