Common Stock (Schedule of Stock Option Activity) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Shares
Outstanding at beginning of period (in shares) | shares	37
Granted (in shares) | shares	0
Exercised (shares) | shares	(26)
Canceled (in shares) | shares	(1)
Outstanding at end of period (in shares) | shares	10
Exercisable (in shares) | shares	10
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 50.40
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	45.88
Canceled (in dollars per share) | $ / shares	43.63
Outstanding at end of period (in dollars per share) | $ / shares	61.93
Exercisable (in dollars per share) | $ / shares	$ 61.93