Long-term Debt, Line of Credit and Derivatives - Provisions of the revolving line of credit and accordion (Details) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Aug. 05, 2016	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Aug. 05, 2015
Debt Instrument [Line Items]
Repayments of debt			$ 29,021,000	$ 4,541,000
Borrowings from Credit Facility			32,000,000	$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Fair value of amount outstanding		$ 12,000,000	12,000,000
Line of credit facility, remaining borrowing capacity		36,900,000	36,900,000
Repayments of debt		14,000,000
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					$ 50,000,000
Minimum additional borrowing amount					1,000,000
Amount over minimum additional borrowing amount, integral multiples					250,000
Revolving Credit Facility | Letter of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					20,000,000
Letters of credit outstanding, amount		1,100,000	1,100,000
Revolving Credit Facility | Bridge Loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					5,000,000
Minimum additional borrowing amount					250,000
Amount over minimum additional borrowing amount, integral multiples					$ 50,000
Term Loan | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		135,000,000	135,000,000
Fair value of amount outstanding		$ 101,600,000	101,600,000
Repayments of debt			$ 1,600,000
Term Loan | Line of Credit | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Interest rate, effective percentage		4.00%	4.00%
Subsequent Event | Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings from Credit Facility	$ 10,000,000