Income Taxes (Schedule Of Components Of Provision For Income Taxes) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Currently payable:
Federal	$ 136,124,497	$ 129,379,597	$ 108,689,911
State	3,805,000	2,908,000	2,236,000
Foreign	540,000	276,000	978,000
Total	140,469,497	132,563,597	111,903,911
Net deferred:
Primarily federal	22,500,000	12,558,000	14,818,000
Provision for income taxes	$ 162,969,497	$ 145,121,597	$ 126,721,911