Earnings Per Common Share and Stockholders' Equity (Share Repurchase Program and Treasury Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended	11 Months Ended
	Feb. 25, 2021	Dec. 31, 2020	Sep. 30, 2021	Feb. 25, 2021	Sep. 30, 2021	Sep. 30, 2021	Nov. 30, 2020	Oct. 18, 2020
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized amount								$ 500,000
Treasury stock acquired, shares						9,100,000
Treasury stock acquired, value			$ 1,340		$ 99,415
Treasury stock acquired, average price per common share						$ 29.04
Treasury stock, shares		6,516,525	9,936,715		9,936,715	9,936,715
Treasury stock, carrying value		$ 151,600	$ 260,600		$ 260,600	$ 260,600
Open Market
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired, shares						5,100,000
Treasury stock acquired, value						$ 149,400
Accelerated Share Repurchase Agreement
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired, shares	500,000	3,500,000
Accelerated share repurchase agreement, aggregate amount							$ 115,000
Accelerated share repurchases, price paid per share				$ 28.45