Long-term Debt and Related Matters - Narrative (Details)	Jun. 26, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jan. 29, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 25, 2020 USD ($)
Line of Credit Facility
Line of credit facility, amount outstanding		$ 37,025,000		$ 44,777,000
Second Amendment
Line of Credit Facility
Minimum aggregate indebtedness			$ 3,000,000
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company
Line of Credit Facility
Line of credit, covenants, basket for dispositions					$ 25,000,000
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment
Line of Credit Facility
Revolving facility usage	1.50
Line of credit, covenants, basket for dispositions	$ 40,000,000
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment | Inventories
Line of Credit Facility
Minimum working capital to revolving facility usage ratio	0.50
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment | Accounts Receivable
Line of Credit Facility
Minimum working capital to revolving facility usage ratio	0.85
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment | Debt Instrument, Redemption, Period One
Line of Credit Facility
Minimum leverage ratio	3.25
Maximum liquidity ratio required	3.50
Minimum interest coverage ratio	1.00
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment | Debt Instrument, Redemption, Period Two
Line of Credit Facility
Minimum leverage ratio	3.00
Maximum liquidity ratio required	3.25
Minimum interest coverage ratio	1.05
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment | Debt Instrument, Redemption, Period Three
Line of Credit Facility
Minimum leverage ratio	2.75
Maximum liquidity ratio required	3.00
Minimum interest coverage ratio	1.15
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | First Amendment | Debt Instrument, Redemption, Period Four
Line of Credit Facility
Minimum interest coverage ratio	1.25
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Overnight Bank Funding Rate | First Amendment
Line of Credit Facility
Debt instrument, basis spread on variable rate	0.50%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Euro-rate | First Amendment
Line of Credit Facility
Debt instrument, basis spread on variable rate	1.00%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Euro-rate | First Amendment | Minimum
Line of Credit Facility
Debt instrument, basis spread on variable rate	2.00%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Euro-rate | First Amendment | Maximum
Line of Credit Facility
Debt instrument, basis spread on variable rate	3.00%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Base Rate | First Amendment
Line of Credit Facility
Debt instrument, basis spread on variable rate	1.00%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Base Rate | First Amendment | Minimum
Line of Credit Facility
Debt instrument, basis spread on variable rate	1.00%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Base Rate | First Amendment | Maximum
Line of Credit Facility
Debt instrument, basis spread on variable rate	2.00%
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Revolving credit facility
Line of Credit Facility
Line of credit facility, amount outstanding		497,000
Potential increase to borrowing capacity	$ 50,000,000
Liquidity covenant	25,000,000
Acquisition consideration threshold, per acquisition	50,000,000
Aggregate acquisition threshold for four consecutive periods where acquisitions occurred	50,000,000
Aggregate acquisition consideration threshold	100,000,000
Line of credit facility, current borrowing capacity		$ 77,478,000
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Revolving credit facility | First Amendment
Line of Credit Facility
Line of credit facility, maximum borrowing capacity	140,000,000
Line of credit facility, accordion feature, decrease limit	120,000,000
Line of credit, accordion feature, lower borrowing capacity option	25,000,000			$ 5,000,000
PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A., Citizens Bank of Pennsylvania, and Branch Banking and Trust Company | Secured debt | First Amendment
Line of Credit Facility
Debt instrument, face amount	25,000,000
Line of credit facility, amount outstanding	$ 22,500,000