Convertible Debt and Notes Payable - Term Loans, Other Notes Payable and Revolver (Details) - USD ($)	3 Months Ended	6 Months Ended	9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Mar. 24, 2021	Jan. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 01, 2019	Jul. 01, 2019	Jun. 30, 2017
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	$ 320,000,000		$ 320,000,000
Other Notes Payable	13,340,000		13,340,000				$ 72,505,000
Term Loan	290,151,000		290,151,000				$ 0
The Military Mutual Ltd [Member]
Debt and Capital Lease Obligations [Line Items]
Other Receivables	$ 28,400,000		$ 28,400,000
BMO Harris Bank | Revolving Credit Facility
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization				$ 300,000
Letter of credit, borrowing capacity								$ 25,000,000
Notes Payable to Banks
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount										$ 4,000,000	$ 28,200,000
Short-term Debt, Percentage Bearing Variable Interest Rate	3.75%		3.75%
Interest Expense, Debt, Excluding Amortization				$ 800,000
Term Loan
Debt and Capital Lease Obligations [Line Items]
Term Loan	$ 290,151,000		$ 290,151,000
Insurance Note
Debt and Capital Lease Obligations [Line Items]
Interest rate						2.01%
Debt Instrument, Periodic Payment, Principal			300,000
Other Notes Payable	$ 800,000		800,000			$ 3,000,000
Corporate Debt
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization			$ 100,000
Interest rate	6.00%		6.00%
Debt Instrument, Periodic Payment, Principal			$ 100,000
Other Long-term Debt	$ 1,700,000		1,700,000						$ 2,600,000
Purple Protect Asset S-91
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization	500,000		2,600,000
Interest rate				5.80%			6.07%
Other Notes Payable				$ 72,000,000
Debt Issuance Costs, Gross				1,700,000
Repayments of Other Debt		$ 60,000,000
2028 Term Loan | Term Loan
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount					$ 300,000,000
Interest Expense, Debt, Excluding Amortization	3,100,000		6,300,000
Interest rate					3.25%
Debt Issuance Costs, Gross					$ 6,600,000
Term Loan	297,800,000		297,800,000
Unamortized discount					$ 1,500,000
Debt Instrument, Interest Rate, Effective Percentage					4.46%
Spike Line
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization				$ 200,000
Maximum | Spike Line
Debt and Capital Lease Obligations [Line Items]
Line of Credit, Current	$ 70,000,000		$ 70,000,000