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Investments - Amortized Cost and Fair Values of Debt Securities (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Amortized cost |  |
Due in one year or less | $ 367,161 |
Due after one year through five years | 1,900,096 |
Due after five years through ten years | 930,951 |
Due after ten years | 1,132,469 |
Total debt securities with single maturity date, amortized cost | 4,330,677 |
Amortized Cost | 5,357,436 | $ 5,196,784
Fair Value |  |
Due in one year or less | 367,474 |
Due after one year through five years | 1,930,664 |
Due after five years through ten years | 976,031 |
Due after ten years | 1,203,911 |
Total debt securities with single maturity date, fair value | 4,478,080 |
Total at end of period | 5,504,823 | 5,151,987
Asset backed securities (“ABS”) |  |
Amortized cost |  |
Total debt securities without single maturity date, amortized cost | 215,016 |
Amortized Cost | 215,016 | 111,953
Fair Value |  |
Total debt securities without single maturity date, fair value | 217,701 |
Total at end of period | 217,701 | 112,033
Residential mortgage backed securities (“RMBS”) |  |
Amortized cost |  |
Total debt securities without single maturity date, amortized cost | 213,024 |
Amortized Cost | 213,024 | 189,238
Fair Value |  |
Total debt securities without single maturity date, fair value | 208,497 |
Total at end of period | 208,497 | 178,961
Commercial mortgage backed securities (“CMBS”) |  |
Amortized cost |  |
Total debt securities without single maturity date, amortized cost | 268,189 |
Amortized Cost | 268,189 | 276,352
Fair Value |  |
Total debt securities without single maturity date, fair value | 271,889 |
Total at end of period | 271,889 | 267,660
Collateralized loan obligations (“CLO”) |  |
Amortized cost |  |
Total debt securities without single maturity date, amortized cost | 330,530 |
Amortized Cost | 330,530 | 310,587
Fair Value |  |
Total debt securities without single maturity date, fair value | 328,656 |
Total at end of period | $ 328,656 | $ 305,295

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- Definition This item represents the total debt securities, categorized neither as held-to-maturity nor trading securities, which have a single maturity date, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454 + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 + Details
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=75019621&loc=d3e62586-112803 + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 + Details
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- Definition Amortized cost of investment in debt security measured at fair value with change recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 + Details
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