Shares and Stockholders' Equity (Reconciliation Of The Denominator Calculations Of Basic And Diluted EPS) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
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	236,463,183	251,849,316	239,069,774	253,662,410
Shares to cover exercise of outstanding warrants	1,098,405	1,356,262	1,100,176	1,604,192
Shares to cover non-vested stock	939,526	1,220,690	1,030,627	1,357,152
Average stock options outstanding during the period	2,110,327	3,676,185	1,958,486	3,759,166
Assumed acquisition of shares with assumed proceeds from exercising outstanding warrants	(265,103)	(240,814)	(278,312)	(295,871)
Assumed acquisition of shares with assumed proceeds and benefits from exercising stock options (at average market price for the period)	(1,523,490)	(2,655,466)	(1,428,150)	(2,701,424)
Shares repurchaseable from measured but unrecognized stock option expense	(38,377)	(65,873)	(19,740)	(63,196)
Average deferred compensation shares	1,101,384		1,070,657	1,022,523
Weighted-average shares, as used in diluted calculation	239,885,855	255,140,300	242,503,518	258,344,952