Acquisition of Business - Narrative (Details) - American Access Casualty Company $ in Millions		3 Months Ended	12 Months Ended
Nov. 23, 2020 USD ($)	Jun. 30, 2021 agent	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Cash consideration	$ 371.0
Direct premiums			$ 350.0
Number of independent agents \| agent		600

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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