Acquisitions Schedule of Revenue and Income (Details) - USD ($) $ in Thousands	8 Months Ended	9 Months Ended	12 Months Ended
Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
AmCo Holding Company
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual		$ 134,386	$ 193,168
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual		$ 14,778	18,673
Interboro Insurance Company
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 28,573		27,024	$ 31,780
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	$ 9,645		$ (2,906)	$ 385

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This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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