Line of Credit and Long-Term Debt - Line of Credit (Details)		3 Months Ended	6 Months Ended
	Oct. 13, 2014	Sep. 30, 2013 USD ($)	Jun. 30, 2017 USD ($) covenant	Dec. 31, 2016 USD ($)
Line of Credit Facility [Line Items]
Total short-term and long-term debt			$ 91,968,000	$ 81,567,000
Level 2 | Interest Rate Swap
Line of Credit Facility [Line Items]
Notional Amount			$ 67,757,000
Interest pay rate			4.11%
Other Liabilities | Level 2 | Interest Rate Swap
Line of Credit Facility [Line Items]
Notional Amount				69,439,000
Selected LIBOR rate
Line of Credit Facility [Line Items]
Interest rate on line of credit, variable rate			1.50%
LIBOR for a fixed rate term
Line of Credit Facility [Line Items]
Interest rate on line of credit, variable rate			1.50%
Revolving line of credit
Line of Credit Facility [Line Items]
Total short-term and long-term debt			$ 20,000,000	7,700,000
Long-term debt				$ 7,700,000
Promissory note agreement
Line of Credit Facility [Line Items]
Long-term debt			3,829,000
Debt instrument face amount		$ 4,750,000
Stated interest rate		4.25%
Periodic principal and interest payments		$ 102,700
Term Notes
Line of Credit Facility [Line Items]
Line of credit amount			$ 70,000,000
Interest pay rate			4.11%
Periodic payments, interest only period			2 years
Term Notes | Selected LIBOR rate
Line of Credit Facility [Line Items]
Interest rate on line of credit, variable rate			1.70%
Revolving line of credit
Line of Credit Facility [Line Items]
Line of credit amount			$ 30,000,000
Commitment fee percentage	0.10%
Number of debt covenants | covenant			3
Minimum liquid assets			$ 20,000,000
Revolving line of credit | Maximum
Line of Credit Facility [Line Items]
Debt equity ratio			0.75
Revolving line of credit | Minimum
Line of Credit Facility [Line Items]
Debt service coverage ratio			1.25