Shareholders' Equity (Narrative) (Details) - USD ($)				1 Months Ended					3 Months Ended		6 Months Ended
	Jul. 22, 2020	Oct. 30, 2017	Jul. 29, 2016	Aug. 31, 2020	May 31, 2020	Apr. 30, 2020	Mar. 31, 2020	Feb. 29, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jul. 28, 2020	Jul. 27, 2020	Jul. 31, 2018
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, repurchased cost										$ 28,100,000	$ 34,400,000	$ 48,100,000
Quarterly dividends declared						$ 0.20		$ 0.20
Dividends declared					$ 0.20		$ 0.20		$ 0.20	$ 0.175	$ 0.40	$ 0.35
Dividends payable, date to be paid, year and month					2020-05		2020-03
Forecast [Member]
Equity Class Of Treasury Stock [Line Items]
Dividends declared				$ 0.20
Dividends payable, date to be paid, year and month				2020-08
Subsequent Event [Member]
Equity Class Of Treasury Stock [Line Items]
Quarterly dividends declared	$ 0.20
Common Stock
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, expiration date			Jul. 31, 2018
Stock repurchase program, additional authorized amount		$ 250,000,000.0													$ 300,000,000.0
Shares repurchase program, extended expiration date		Oct. 31, 2020
Shares repurchase program, shares repurchased										316,005	382,170	647,691
Common Stock | Share Repurchase Program Excluding Accelerated Share Repurchase
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, shares repurchased											400,000
Shares repurchase program, repurchased cost											$ 34,400,000
Shares repurchase program, average price per share											$ 89.99
Common Stock | Share Repurchase Program Including Accelerated Share Repurchase
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, shares repurchased											9,600,000
Shares repurchase program, repurchased cost											$ 596,200,000
Shares repurchase program, average price per share											$ 62.13
Common Stock | Maximum [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, authorized amount			$ 150,000,000.0												$ 700,000,000.0
Common Stock | Subsequent Event [Member]
Equity Class Of Treasury Stock [Line Items]
Stock repurchase program, additional authorized amount													$ 500,000,000.0
Common Stock | Subsequent Event [Member] | Maximum [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, authorized amount														$ 1,200,000,000