Debt - Margin for Borrowings under Revolving Credit Facility (Details) - Revolving Credit Facility - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019
Minimum | III
Line of Credit Facility [Line Items]
Availability of borrowing		$ 30,000,000
Minimum | II
Line of Credit Facility [Line Items]
Availability of borrowing		15,000,000
Maximum | II
Line of Credit Facility [Line Items]
Availability of borrowing		30,000,000
Maximum | I
Line of Credit Facility [Line Items]
Availability of borrowing		$ 15,000,000
Tranche A | Base Rate Loans | III
Line of Credit Facility [Line Items]
Basis spread (as a percent)		0.50%
Tranche A | Base Rate Loans | II
Line of Credit Facility [Line Items]
Basis spread (as a percent)		0.75%
Tranche A | Base Rate Loans | I
Line of Credit Facility [Line Items]
Basis spread (as a percent)		1.00%
Tranche A | LIBOR Revolver Loans | III
Line of Credit Facility [Line Items]
Basis spread (as a percent)		1.50%
Tranche A | LIBOR Revolver Loans | II
Line of Credit Facility [Line Items]
Basis spread (as a percent)		1.75%
Tranche A | LIBOR Revolver Loans | I
Line of Credit Facility [Line Items]
Basis spread (as a percent)		2.00%
Tranche B | Base Rate Loans | III
Line of Credit Facility [Line Items]
Basis spread (as a percent)	1.50%
Tranche B | Base Rate Loans | II
Line of Credit Facility [Line Items]
Basis spread (as a percent)	1.75%
Tranche B | Base Rate Loans | I
Line of Credit Facility [Line Items]
Basis spread (as a percent)	2.00%
Tranche B | LIBOR Revolver Loans | III
Line of Credit Facility [Line Items]
Basis spread (as a percent)	2.50%
Tranche B | LIBOR Revolver Loans | II
Line of Credit Facility [Line Items]
Basis spread (as a percent)	2.75%
Tranche B | LIBOR Revolver Loans | I
Line of Credit Facility [Line Items]
Basis spread (as a percent)	3.00%