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Insurance Activity - Schedule of Premiums Assumed and Earned (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Insurance [Abstract] |  |  |  |
Net premiums assumed (released) | $ 18 | $ 319 | $ 2 | $ 524
Change in unearned premiums |  | 10 | 39 | 235
Premiums earned | $ 18 | $ 329 | $ 41 | $ 759

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- Definition Amount of increase (decrease) unearned premiums written. Excludes portion of unearned premiums amortized into income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
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- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(c)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915 + Details
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- Definition Net premiums assumed (released). + References No definition available. + Details
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