Derivatives and Hedging Activities - Fair Value of Derivatives and Balance Sheet Classification (Details) - Designated as hedging instrument - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 1,097,223	$ 739,606
Liability Derivatives	(2,126,536)	(3,067,572)
Interest rate products | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	161,659	243
Interest rate products | Other assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	225,848	84,058
Interest rate products | Other liabilities - current
Derivatives, Fair Value [Line Items]
Liability Derivatives	0	(71,915)
Cross currency contract | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	709,716	655,305
Cross currency contract | Long-term derivative liability
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ (2,126,536)	$ (2,995,657)