Lines of Credit - Additional Information (Details) - SIC Credit Facility - USD ($)		3 Months Ended
	Jun. 28, 2018	Mar. 31, 2019	Mar. 31, 2018
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 90,000,000
Line of credit facility, increased amount	10,000,000
Line of credit facility maximum borrowing capacity upon satisfaction of certain conditions	130,000,000
Letter of credit facility maximum aggregate stated amount	$ 15,000,000
Discerption of debt instrument variable rate basis		LIBOR based rate plus an applicable margin varying from one hundred twenty five basis points (1.25%) to one hundred seventy five basis points (1.75%) based on the borrowers’ average daily availability determined quarterly, or a base rate determined on the highest of three alternative rates based on the Prime rate, or the Federal Funds rate plus a fifty basis point (0.50%) margin, or a LIBOR based rate plus a two hundred basis point (2.00%) margin.
Increase in floating interest rate, basis points	2.00%
Line of credit maturity date	Jun. 28, 2023
Line of credit, outstanding amount		$ 30,000,000
Debt issuance costs		500,000
Non-cash interest expense		30,000	$ 0
Unamortized debt issuance costs related to the RDS and ASG credit agreement		$ 400,000
LIBOR
Line Of Credit Facility [Line Items]
Debt instrument margin basis point	2.00%
LIBOR | Minimum
Line Of Credit Facility [Line Items]
Debt instrument margin basis point	1.25%
LIBOR | Maximum
Line Of Credit Facility [Line Items]
Debt instrument margin basis point	1.75%
Federal Funds Rate
Line Of Credit Facility [Line Items]
Debt instrument margin basis point	0.50%