Equity (Stock Repurchase Program) (Details) - USD ($) $ / shares in Units, shares in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Stock repurchase program
Shares repurchased and retired during period (in shares)	4.2	3.7
Common stock value repurchased including acquisition costs	$ 91,900,000	$ 41,400,000
Average cost per share of repurchased shares (in dollars per share)	$ 21.70	$ 11.32
Maximum
Stock repurchase program
Stock repurchase program, authorized amount	$ 50,000,000.0
Stock repurchase program remaining authorized amount	$ 30,900,000