Stock-Based Compensation (Summary Of The Status Of Nonvested Share Awards) (Details)	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Nonvested Share Awards [Roll Forward]
Nonvested, Shares, Beginning Balance | shares	1,180,940
Granted, Shares | shares	188,649
Vested, Shares | shares	(307,548)
Forfeited, Shares | shares	(9,974)
Nonvested, Shares, Ending Balance | shares	1,052,067
Nonvested, Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 43.24
Granted , Weighted Average Grant Date Fair Value | $ / shares	61.71
Vested , Weighted Average Grant Date Fair Value | $ / shares	32.90
Forfeited , Weighted Average Grant Date Fair Value | $ / shares	48.48
Nonvested , Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 49.52