Derivatives and Hedging Activities - Effect of Cash Flow Hedge Accounting on Accumulated Other Comprehensive Income (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivative financial instruments, net of tax of $50,362, $834,099, $335,560 and $416,203, respectively	$ (131,905)	$ 1,858,182	$ 695,763	$ 1,097,056
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	(232,239)	1,831,921	543,598	1,053,778
Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	230,698	236,103	486,064	417,324
Gain (loss) on foreign currency transactions
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	(569,158)	2,428,813	297,788	1,145,146
Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivative financial instruments, net of tax of $50,362, $834,099, $335,560 and $416,203, respectively	(182,267)	2,692,281	1,031,323	1,513,259
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	(338,460)	2,664,915	783,852	1,562,469
Cash flow hedging | Gain (loss) on foreign currency transactions
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	(569,158)	2,428,813	297,788	1,145,146
Interest rate products | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivative financial instruments, net of tax of $50,362, $834,099, $335,560 and $416,203, respectively	(70,188)	95,236	(130,997)	363,785
Interest rate products | Cash flow hedging | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	30,673	17,297	83,214	(20,982)
Cross currency contract | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivative financial instruments, net of tax of $50,362, $834,099, $335,560 and $416,203, respectively	(112,079)	2,597,045	1,162,320	1,149,474
Cross currency contract | Cash flow hedging | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income	$ 200,025	$ 218,805	$ 402,850	$ 438,305