Long-term Debt and Related Matters - Narrative (Details)	Aug. 13, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Line of Credit Facility
Line of credit facility, amount outstanding		$ 32,268,000	$ 44,777,000
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Fourth Amended And Restated Credit Agreement
Line of Credit Facility
Minimum interest coverage ratio	1.05
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Fourth Amended And Restated Credit Agreement | Debt Instrument, Redemption, Period One
Line of Credit Facility
Minimum leverage ratio	3.25
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Fourth Amended And Restated Credit Agreement | Debt Instrument, Redemption, Period Two
Line of Credit Facility
Minimum leverage ratio	3.5
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Overnight Bank Funding Rate | Fourth Amended And Restated Credit Agreement
Line of Credit Facility
Debt instrument, basis spread on variable rate	0.50%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | LIBOR | Fourth Amended And Restated Credit Agreement
Line of Credit Facility
Debt instrument, basis spread on variable rate	1.00%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | LIBOR | Fourth Amended And Restated Credit Agreement | Minimum
Line of Credit Facility
Debt instrument, basis spread on variable rate	1.25%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | LIBOR | Fourth Amended And Restated Credit Agreement | Maximum
Line of Credit Facility
Debt instrument, basis spread on variable rate	2.25%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Base Rate | Fourth Amended And Restated Credit Agreement | Minimum
Line of Credit Facility
Debt instrument, basis spread on variable rate	0.25%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Base Rate | Fourth Amended And Restated Credit Agreement | Maximum
Line of Credit Facility
Debt instrument, basis spread on variable rate	1.25%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Revolving credit facility
Line of Credit Facility
Liquidity covenant	$ 15,000,000
Line of credit facility, amount outstanding		665,000
Line of credit facility, current borrowing capacity		$ 97,067,000
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Revolving credit facility | Debt Instrument, Redemption, Period One
Line of Credit Facility
Acquisition consideration threshold, per acquisition	$ 50,000,000
Acquisition consideration threshold percent	275.00%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Revolving credit facility | Debt Instrument, Redemption, Period Two
Line of Credit Facility
Acquisition consideration threshold, per acquisition	$ 75,000,000
Acquisition consideration threshold percent	175.00%
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Revolving credit facility | Prior Credit Facility
Line of Credit Facility
Line of credit facility increase over previous commitment	$ 15,000,000
PNC Bank N.A. Citizens Bank N.A. Wells Fargo Bank National Association Bank of America N.A. And BMO Harris Bank National Association | Revolving credit facility | Fourth Amended And Restated Credit Agreement
Line of Credit Facility
Debt instrument term	5 years
Line of credit facility, maximum borrowing capacity	$ 130,000,000
Line of credit, accordion feature, lower borrowing capacity option	25,000,000
Maximum increase in commitments	$ 50,000,000