Stock-Based Compensation (Summary Of The Status Of Nonvested Share Awards) (Details)	9 Months Ended
	Sep. 30, 2019 $ / shares shares
Nonvested Share Awards [Roll Forward]
Nonvested, Shares, Beginning Balance | shares	1,180,940
Granted, Shares | shares	199,252
Vested, Shares | shares	(312,122)
Forfeited, Shares | shares	(11,894)
Nonvested, Shares, Ending Balance | shares	1,056,176
Nonvested, Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 43.24
Granted , Weighted Average Grant Date Fair Value | $ / shares	61.57
Vested , Weighted Average Grant Date Fair Value | $ / shares	33.00
Forfeited , Weighted Average Grant Date Fair Value | $ / shares	49.17
Nonvested , Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 49.65