Common Share Repurchases (Details) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($) shares	Sep. 30, 2020 USD ($) $ / shares shares
Treasury Stock Transactions, Excluding Value of Shares Reissued [Abstract]
Number of shares repurchased (in shares) | shares	0	3,500,000
Cost of shares repurchased		$ 425,000
Average cost per share repurchased (in dollars per share) | $ / shares		$ 123.09
Number of shares acquired to cover tax withholding costs and exercise costs (in shares) | shares	1,368	300,000
Cost of shares acquired to cover tax withholding costs and exercise costs	$ 159	$ 46,000
Remaining capacity under share repurchase authorization	$ 1,360,000	$ 1,360,000