Common Stock Stock Repurchase (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 14, 2020	Apr. 30, 2019
Equity, Class of Treasury Stock [Line Items]
Document Period End Date				Sep. 30, 2020
Stock Repurchase Program, Authorized Amount						$ 525,000	$ 200,000
Payments for Repurchase of Common Stock				$ 8,412	$ 3,874
Treasury Stock, Common [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased During Period, Shares	(1,266,000)	(1,228,310)	(3,136,406)	1,300,000
Payments for Repurchase of Common Stock				$ 23,800
Treasury Stock remaining to be repurchased				$ 346,800