Debt - Credit Facilities (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jun. 30, 2021	Sep. 30, 2021	May 31, 2021	Dec. 31, 2020
Borrowing under Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Accrued interest included in balance		$ 100,000
Line of credit | A&R Credit Agreement
Line of Credit Facility [Line Items]
Maximum revolver amount	$ 50,000,000
Outstanding balance of line of credit facilities			$ 21,000,000
Line of credit | Borrowing under Wells Fargo Credit Facility
Line of Credit Facility [Line Items]
Maximum revolver amount	$ 50,000,000
Outstanding balance of line of credit facilities		$ 20,200,000
Cash balance for borrowing	100.00%
Cash balance max borrowing (up to)	$ 15,000,000
Maximum revolver increase	$ 25,000,000
Commitment fee percent	0.25%
Maximum indebtedness under debt covenant	$ 20,000,000
Unused borrowing capacity	$ 5,000,000
Weighted average interest rate		1.90%		2.01%
Unused part of credit facility		$ 15,900,000
Minimum required unused borrowing capacity		$ 5,000,000
Line of credit | Borrowing under Wells Fargo Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Weighted average interest rate		1.90%
Line of credit | Borrowing under Wells Fargo Credit Facility | Minimum
Line of Credit Facility [Line Items]
Revolver accounts receivable (up to)	90.00%
Line of credit | Borrowing under Wells Fargo Credit Facility | Minimum | LIBOR
Line of Credit Facility [Line Items]
TIBOR interest rate spread	1.50%
Line of credit | Borrowing under Wells Fargo Credit Facility | Minimum | Prime rate
Line of Credit Facility [Line Items]
TIBOR interest rate spread	0.50%
Line of credit | Borrowing under Wells Fargo Credit Facility | Maximum | LIBOR
Line of Credit Facility [Line Items]
TIBOR interest rate spread	1.75%
Line of credit | Borrowing under Wells Fargo Credit Facility | Maximum | Prime rate
Line of Credit Facility [Line Items]
TIBOR interest rate spread	0.75%