Comprehensive Income (Reclassification Out of Accumulated Other Comprehensive Income) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Provision for Income Taxes	$ (41,123,468)	$ (35,891,736)	$ (80,413,086)	$ (67,126,185)
Amounts Reclassified from Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	(375,579)	1,245,234	(1,035,313)	2,943,210
Amounts Reclassified from Other Comprehensive Income | Unrealized gains on available-for-sale securities:
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Realized (loss) gain on sale of securities	(24,733)	1,915,743	(487,457)	4,528,014
Provision for Income Taxes	8,657	(670,509)	170,610	(1,584,804)
Total reclassifications for the period	(16,076)	1,245,234	(316,847)	2,943,210
Amounts Reclassified from Other Comprehensive Income | Unrealized gains (losses) on derivatives
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Realized (loss) gain on sale of securities	(553,083)	0	(1,105,333)	0
Provision for Income Taxes	193,580	0	386,867	0
Total reclassifications for the period	$ (359,503)	$ 0	$ (718,466)	$ 0