Accounting for Stock-Based Compensation (Schedule of Share-based Compensation, Restricted Stock, Activity) (Details) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Unvested Shares	3,308,907	2,643,919	2,969,285
Granted, Shares	1,989,000	1,987,000	1,502,000
Vested, Shares	(1,160,667)	(1,154,670)	(1,586,855)
Forfeited, Shares	(279,838)	(167,342)	(240,511)
Ending Balance, Unvested Shares	3,857,402	3,308,907	2,643,919
Beginning of Period, Weighted Average Grant Date Fair Value	$ 7.00	$ 16.17	$ 29.39
Granted, Weighted Average Grant Date Fair Value	4.94	4.54	9.10
Vested, Weighted Average Grant Date Fair Value	8.89	23.22	33.91
Forfeited, Weighted Average Grant Date Fair Value	5.60	10.29	18.20
End of Period, Weighted Average Grant Date Fair Value	$ 5.47	$ 7.00	$ 16.17