Net Income Per Common Share (Ant-Dilutive Schedule) (Details) - $ / shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Average outstanding options	443	2,056	446	1,633
Minimum | Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Range of exercise prices	$ 79.01	$ 39.10	$ 70.18	$ 39.10
Maximum | Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Range of exercise prices	$ 95.25	$ 95.25	$ 95.25	$ 95.25