Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic Earnings (Loss) Per Share
Net income (Loss)		$ 86,506,418	$ (2,374,033)	$ 199,957,288	$ 87,131,768
Less: Dividends and undistributed earnings allocated to participating securities		1,324,767	439,327	2,974,367	1,245,275
Net Income (Loss) available to common shareholders		$ 85,181,651	$ (2,813,360)	$ 196,982,921	$ 85,886,493
Basic weighted average shares outstanding		238,602,197	241,684,323	238,198,668	243,983,276
Net (Loss) Income per share - Basic (in dollars per share)	[1]	$ 0.36	$ (0.01)	$ 0.83	$ 0.35
Diluted Earnings (Loss) Per Share
Allocation of Net Income (Loss) used in basic computation		$ 85,181,651	$ (2,813,360)	$ 196,982,921	$ 85,886,493
Reallocation of undistributed earnings		3,980	0	10,464	1,697
Net Income (Loss) available to common shareholders - Diluted		$ 85,185,631	$ (2,813,360)	$ 196,993,385	$ 85,888,190
Number of shares used in basic computation		238,602,197	241,684,323	238,198,668	243,983,276
Additional weighted average dilutive common stock equivalents (in shares)		1,130,301	0	1,218,528	1,085,380
Diluted weighted average shares outstanding		239,732,498	241,684,323	239,417,196	245,068,656
Net Income (Loss) per share - Diluted (in dollars per share)	[1]	$ 0.36	$ (0.01)	$ 0.82	$ 0.35
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive		270,475	1,636,661	137,484	428,948

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