Long-Term Debt and Credit Facility - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Subtotal	$ 365,358	$ 374,026
Less – Current maturities of long-term debt	26,556	19,835
Less – Unamortized loan costs	2,739	3,406
Total	336,063	350,785
Term Note
Debt Instrument [Line Items]
Term note, due October 30, 2020, annualized rates of 3.26% and 3.08%, respectively	$ 315,000	$ 328,125
Current effective interest rate	3.26%	3.08%
Line of Credit
Debt Instrument [Line Items]
Line of credit, 3.23% and 2.96%, respectively	$ 50,000	$ 36,000
Current effective interest rate	3.23%	2.96%
Other notes
Debt Instrument [Line Items]
Other notes with interest rates from 3.26% to 6.50%	$ 358	$ 9,901
Other notes | Minimum
Debt Instrument [Line Items]
Current annualized interest rate	3.26%	3.26%
Other notes | Maximum
Debt Instrument [Line Items]
Current annualized interest rate	6.50%	6.50%