Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic Earnings Per Share
NET (LOSS) INCOME		$ (2,374,033)	$ 108,958,625	$ 87,131,768	$ 213,239,036
Less: Dividends and undistributed earnings allocated to participating securities		439,327	1,256,243	1,245,275	2,348,020
Net (Loss) Income available to common shareholders		$ (2,813,360)	$ 107,702,382	$ 85,886,493	$ 210,891,016
Basic weighted average shares outstanding (in shares)		241,684,323	255,219,868	243,983,276	256,350,600
Net (Loss) Income per share - Basic (in dollars per share)	[1]	$ (0.01)	$ 0.42	$ 0.35	$ 0.82
Earnings Per Share, Diluted [Abstract]
Allocation of Net (Loss) Income used in basic computation		$ (2,813,360)	$ 107,702,382	$ 85,886,493	$ 210,891,016
Reallocation of undistributed earnings		0	4,848	1,697	8,842
Net (Loss) Income available to common shareholders - Diluted		$ (2,813,360)	$ 107,707,230	$ 85,888,190	$ 210,899,858
Number of shares used in basic computation		241,684,323	255,219,868	243,983,276	256,350,600
Additional weighted average dilutive common stock equivalents (in shares)		0	1,359,753	1,085,380	1,344,285
Diluted weighted average shares outstanding (in shares)		241,684,323	256,579,621	245,068,656	257,694,885
Net (Loss) Income per share - Diluted (in dollars per share)	[1]	$ (0.01)	$ 0.42	$ 0.35	$ 0.82
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive (in shares)		1,636,661	1,013,332	428,948	1,011,948

[1] ⁽¹⁾ Earnings (Loss) Per Share has been adjusted to exclude the portion of net income allocated to participating securities as a result of share-based payment awards.