Shares And Stockholders' Equity (Reconciliation Of The Denominator Calculations Of Basic And Diluted EPS) (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of the denominator (number of shares) in the calculations of basic and diluted earnings (loss) per common share
Weighted-average shares, as used in basic calculation	187,359,884	193,610,225	200,608,737
Shares to cover exercise of outstanding warrants			58,765
Shares to cover non-vested stock	1,357,245	687,240	973,901
Average stock options outstanding during the period	1,844,117	746,742	1,507,049
Assumed acquisition of shares with assumed proceeds from exercising outstanding warrants			(9,594)
Assumed acquisition of shares with assumed proceeds and benefits from exercising stock options (at average market price for the period)	(1,419,165)	(576,582)	(1,033,507)
Shares repurchasable from measured but unrecognized stock option expense	(43,314)	(2,445)	(217)
Weighted-average shares, as used in diluted calculation	189,098,767	194,465,180	202,105,134