Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions		1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 28, 2021	Oct. 31, 2021	Aug. 31, 2021	Sep. 30, 2021	May 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jan. 01, 2021
Class of Stock [Line Items]
Retained earnings				$ 3,102,995		$ 3,102,995		$ 2,642,096
Shares repurchased in period (in shares)				10.0				9.6
Shares repurchased, weighted average price per share				$ 15.01				$ 12.47
Remaining authorized repurchase amount				$ 141,000		141,000
Repurchase of common stock						$ 150,000	$ 119,997
Quarterly cash dividend paid (per share)			$ 0.08		$ 0.06
Cash dividends			$ 27,300		$ 41,100
Cumulative Effect, Period of Adoption, Adjustment
Class of Stock [Line Items]
Retained earnings									$ 68,300
Additional paid in capital									$ 68,300
Subsequent Event
Class of Stock [Line Items]
Shares repurchased in period (in shares)		3.8
Stock repurchase program, authorized amount through 2023	$ 500,000
Repurchase of common stock		$ 60,000
Quarterly cash dividend declared (per share)	$ 0.08