Stock Award Plans, Employee Plan Stock Option Activity (Details) - Employee Stock Award Plan [Member]	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Stock Award Plan Information [Abstract]
Shares available for future grants (in shares)	1,100,687
Stock Options [Member]
Stock Award Plan Information [Abstract]
Term of grant	7 years
Vesting period	3 years
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start (in shares)	486,059
Granted (in shares)	114,600
Exercised (in shares)	(19,851)
Canceled or expired (in shares)	(3,291)
Outstanding at Period End (in shares)	577,517
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start (in dollars per share) | $ / shares	$ 71.65
Granted (in dollars per share) | $ / shares	73.29
Exercised (in dollars per share) | $ / shares	64.42
Canceled or expired (in dollars per share) | $ / shares	95.18
Outstanding at Period End (in dollars per share) | $ / shares	$ 72.09
Stock Appreciation Rights [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start (in shares)
Outstanding at Period End (in shares)	0
RSUs [Member]
Stock Award Plan Information [Abstract]
Vesting period	5 years