Long-term Debt, Line of Credit and Derivatives - Obligations under Debt Arrangements (Details) - USD ($)	1 Months Ended
	May 31, 2019	Mar. 31, 2019	Jul. 31, 2018	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal, current				$ 3,375,000	$ 3,000,000
Principal, long-term				66,665,000	77,500,000
Principal				70,040,000	80,500,000
Deferred Issuance Costs, current				(77,000)	(54,000)
Deferred Issuance Costs, long-term				(1,517,000)	(1,381,000)
Deferred Issuance Costs				1,594,000	1,435,000
Net Value, current				3,298,000	2,946,000
Net Value, long-term				65,148,000	76,119,000
Total debt				$ 68,446,000	79,065,000
Line of Credit Facility
Debt Instrument [Line Items]
Weighted average interest rate				5.86%
Term Loan
Debt Instrument [Line Items]
Net Value, current					2,946,000
Term Loan | Line of Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					60,000,000
Principal, current				$ 3,375,000	3,000,000
Principal, long-term				34,665,000	55,500,000
Principal				38,040,000
Deferred Issuance Costs, current				(77,000)	(54,000)
Deferred Issuance Costs, long-term				(789,000)	(1,168,000)
Net Value, current				3,298,000
Net Value, long-term				33,876,000	54,332,000
Revolving Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				50,000,000
Revolving Line of Credit | Line of Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				50,000,000
Debt issuance expense	$ 400,000
Principal, long-term				32,000,000	22,000,000
Deferred Issuance Costs, long-term				(728,000)	(213,000)
Net Value, long-term				31,272,000	$ 21,787,000
Fourth, Fifth And Sixth Amendments To Credit Agreement | Line of Credit Facility
Debt Instrument [Line Items]
Deferred Issuance Costs				$ 900,000
Fourth Amendment to Credit Agreement | Line of Credit Facility
Debt Instrument [Line Items]
Debt issuance costs			$ 900,000
Fifth Amendment To Credit Agreement | Line of Credit Facility
Debt Instrument [Line Items]
Debt issuance costs		$ 600,000
Sixth Amendment To Credit Agreement | Line of Credit Facility
Debt Instrument [Line Items]
Debt issuance costs	$ 900,000