Income Taxes (Schedule Of Components Of Provision For Income Taxes) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Currently payable:
Federal	$ 133,166,194	$ 136,124,497	$ 129,379,597
State	3,984,000	3,805,000	2,908,000
Foreign	2,440,000	540,000	276,000
Total	139,590,194	140,469,497	132,563,597
Deferred income tax (benefit) expense:
Primarily federal	(14,585,412)	22,500,000	12,558,000
Provision for income taxes	$ 125,004,782	$ 162,969,497	$ 145,121,597