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Investments - Summary of Net Investment Income (Detail) - Successor [Member] - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Investment [Line Items] |  |  |  |
Fixed income securities | $ 66,104 | $ 64,627 | $ 125,527 | $ 130,213
Short-term investments | 374 | 60 | 930 | 101
Loans | 70 | 93 | 176 | 225
Investment expense | (2,180) | (2,502) | (4,283) | (4,929)
Securities available-for-sale and short-term | 64,368 | 62,278 | 122,350 | 125,610
Other investments | 6,390 | 2,475 | 9,229 | 12,126
Total net investment income | 70,758 | 64,753 | 131,579 | 137,736
Gains (losses) on securities held as of reporting date [Member] |  |  |  |
Investment [Line Items] |  |  |  |
Net Realized and Unrealized Gain (Loss) on Trading Securities | 5,240 | 1,419 | 6,948 | 10,042
Trading Securities, Realized Gain (Loss) | 1,498 | 3,069 | 1,531 | 5,453
Other investments | $ 3,742 | $ (1,650) | $ 5,417 | $ 4,589

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- Definition Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.2) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24721-111560 + Details
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