Shareholders' Equity (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount	$ 2,800,000						$ 2,800,000
Common stock surrendered as payment	29	$ 317	$ 102,031	$ 38,950	$ 58,512	$ 62,854
Value of common shares remaining to be repurchased	$ 115,018						$ 115,018
Repurchases in Accordance with Stock Award Agreements [Member]
Equity, Class of Treasury Stock [Line Items]
Acquisition of treasury stock (shares), total	0						58,000
Common stock surrendered as payment							$ 47,976