Convertible Debt and Notes Payable - Term Loans, Other Notes Payable and Revolver (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Jan. 31, 2020	Dec. 31, 2019	Nov. 01, 2019	Jul. 01, 2019	Dec. 14, 2017	Dec. 08, 2017	Jun. 30, 2017
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	$ 395,000,000		$ 395,000,000
Other Notes Payable	73,253,000		73,253,000				$ 2,516,000
The Military Mutual Ltd [Member]
Debt and Capital Lease Obligations [Line Items]
Other Receivables	$ 28,400,000		$ 28,400,000
Notes Payable to Banks
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount									$ 4,000,000.0			$ 28,200,000
Short-term Debt, Percentage Bearing Variable Interest Rate	3.75%		3.75%
Interest Expense, Debt, Excluding Amortization		$ 500,000	$ 800,000	$ 1,400,000
Insurance Note
Debt and Capital Lease Obligations [Line Items]
Interest rate	2.01%		2.01%
Debt Instrument, Periodic Payment, Principal			$ 300,000
Other Notes Payable	$ 800,000		800,000			$ 2,900,000
Revolving Credit Facility | BMO Harris Bank
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	$ 25,000,000		25,000,000
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	$ 2,200,000		2,200,000					$ 2,600,000
Purple Protect Asset S-91
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization			$ 0
Interest rate	6.07%		6.07%
Other Notes Payable	$ 72,000,000		$ 72,000,000
Debt Issuance Costs, Gross	1,700,000		1,700,000
Purple Protect Asset S-91 | Forecast
Debt and Capital Lease Obligations [Line Items]
Interest rate					5.80%
2027 Notes | Senior Notes
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount										$ 18,000,000.0	$ 120,000,000.0
Interest Expense, Debt, Excluding Amortization	2,500,000	$ 2,500,000	7,600,000	$ 7,600,000
Interest rate											7.35%
Debt Issuance Costs, Gross											$ 5,000,000.0
Spike Line
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization	0.0		200,000
Revolving Credit Facility
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization			300,000
Maximum | Spike Line
Debt and Capital Lease Obligations [Line Items]
Line of Credit, Current	$ 70,000,000		$ 70,000,000