Equity (Share Activity) (Narrative) (Details) - USD ($) shares in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Mar. 19, 2020	Dec. 21, 2018	Sep. 11, 2018
Equity, Treasury Stock [Line Items]
Treasury stock acquired (in shares)	3.6
Treasury stock acquired, value	$ 120,228,000	$ 602,000
Stock repurchase program, remaining authorized repurchase amount	$ 158,600,000
September 2018 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Treasury stock acquired (in shares)	0.6
Treasury stock acquired, value	$ 28,800,000
Share repurchase program, amount authorized, value					$ 150,000,000
December 2018 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Treasury stock acquired (in shares)	3.0
Treasury stock acquired, value	$ 91,400,000
Share repurchase program, amount authorized, value				$ 100,000,000
Stock repurchase program, remaining authorized repurchase amount	8,600,000
March 2020 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Share repurchase program, amount authorized, value			$ 150,000,000
Stock repurchase program, remaining authorized repurchase amount	$ 150,000,000