Long-Term Debt and Related Matters - Narrative (Details)		3 Months Ended
	Jun. 26, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jun. 25, 2020 USD ($)	Dec. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)
Line of Credit Facility
Line of credit facility, amount outstanding			$ 44,777,000		$ 33,868,000
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
Basket for dispositions				$ 25,000,000
Liquidity covenant		$ 50,000,000
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
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
Maximum leverage ratio	3.25
Maximum liquidity ratio	3.50
Minimum fixed charge 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
Maximum leverage ratio	3.00
Maximum liquidity ratio	3.25
Minimum fixed charge 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
Maximum leverage ratio	2.75
Maximum liquidity ratio	3.00
Minimum fixed charge 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 fixed charge 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 | 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 | Minimum | First Amendment
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 | Maximum | First Amendment
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 | Minimum | 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 | Maximum | First Amendment
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 | 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 | Revolving Credit Facility
Line of Credit Facility
Line of credit facility, amount outstanding			949,000		492,000
Potential increase to borrowing capacity						$ 50,000,000
Liquidity covenant	$ 25,000,000
Aggregate acquisition consideration threshold, per period	50,000,000
Aggregate acquisition consideration threshold	100,000,000
Line of credit facility, current borrowing capacity			69,274,000		$ 105,640,000
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	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