Long-term Debt, Line of Credit and Derivatives - Obligations under Debt Arrangements (Details) - USD ($)	1 Months Ended	6 Months Ended	12 Months Ended
	May 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt issuance costs			$ 900,000
Principal, current		$ 3,000,000	3,000,000
Principal, long-term		80,000,000	77,500,000
Principal		83,000,000	80,500,000
Deferred Issuance Costs, current		(61,000)	(54,000)
Deferred Issuance Costs, long-term		(1,614,000)	(1,381,000)
Deferred Issuance Costs		(1,675,000)	(1,435,000)
Net Value, current		2,939,000	2,946,000
Net Value, long-term		78,386,000	76,119,000
Total debt		81,325,000	79,065,000
Term Loan | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			60,000,000
Total debt		57,000,000
Revolving line of credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		50,000,000.0
Debt issuance expense	$ 400,000
Revolving line of credit | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		50,000,000.0
Principal, long-term		26,000,000	22,000,000
Deferred Issuance Costs, long-term		(525,000)	(213,000)
Net Value, long-term		25,475,000	21,787,000
Term loan - current | Loans Payable
Debt Instrument [Line Items]
Principal, current		3,000,000	3,000,000
Deferred Issuance Costs, current		(61,000)	(54,000)
Net Value, current		2,939,000	2,946,000
Term loan - long-term | Loans Payable
Debt Instrument [Line Items]
Principal, long-term		54,000,000	55,500,000
Deferred Issuance Costs, long-term		(1,089,000)	(1,168,000)
Net Value, long-term		52,911,000	$ 54,332,000
Fifth Amendment To Credit Agreement | Revolving line of credit
Debt Instrument [Line Items]
Debt issuance costs		600,000
Sixth Amendment To Credit Agreement | Revolving line of credit
Debt Instrument [Line Items]
Debt issuance costs		900,000
Fourth, Fifth And Sixth Amendments To Credit Agreement | Revolving line of credit
Debt Instrument [Line Items]
Debt issuance costs		$ 900,000