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Reinsurance - Summary of Quota Reinsurance Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Effects of Reinsurance [Line Items]
Ceded losses incurred	$ 3,431	$ (3,423)	$ 5,105	$ 4,318
Reinsurance recoverable on loss reserves	18,402	37,051	18,402	37,051	$ 33,328	$ 48,474
Quota Share Reinsurance Agreements, Excluding Captive Agreements
Effects of Reinsurance [Line Items]
Ceded premiums written and earned, net of profit commission	36,525	21,432	64,689	54,468
Ceded losses incurred	3,440	(3,735)	5,116	4,053
Ceding commissions	13,356	12,640	26,765	25,285
Profit commission	37,021	$ 41,769	75,902	$ 71,958
Reinsurance recoverable on loss reserves	$ 18,300		$ 18,300		$ 33,200

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- Definition

Ceded Premiums Written and Earned, Net of Profit Commission

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- Definition

Reinsurance Ceding Commission Earned

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Reinsurance, Profit Commission

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=99397103&loc=d3e6811-158387

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- Definition

Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=99404803&loc=d3e21412-158489

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
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-URI http://asc.fasb.org/extlink&oid=99397103&loc=d3e6824-158387

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
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-URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437

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-SubTopic 40
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-URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437

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