Shareholders' Equity and Common Stock Equivalents - Stock Option Information by Ranges of Exercise Prices (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options (in shares)	908,557	774,821	719,015
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 37.82	$ 36.65
Total Outstanding Options, Weighted Average Remaining Term	7 years 5 months 9 days
Vested and Exercisable Options (in shares)	368,700	271,116
Vested and Exercisable Options, Weighted Average Option Price per Share (in usd per share)	$ 34.81	$ 31.42	$ 27.12
Vested and Exercisable Options, Weighted Average Remaining Term	6 years 1 month 9 days
Minimum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 42.95
Maximum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 44.75
Range One
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options (in shares)	11,100
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 22.34
Total Outstanding Options, Weighted Average Remaining Term	4 months 9 days
Vested and Exercisable Options (in shares)	11,100
Vested and Exercisable Options, Weighted Average Option Price per Share (in usd per share)	$ 22.34
Vested and Exercisable Options, Weighted Average Remaining Term	4 months 9 days
Range One | Minimum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 20.60
Range One | Maximum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 22.69
Range Two
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options (in shares)	271,579
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 30.94
Total Outstanding Options, Weighted Average Remaining Term	5 years 7 months 24 days
Vested and Exercisable Options (in shares)	222,499
Vested and Exercisable Options, Weighted Average Option Price per Share (in usd per share)	$ 30.92
Vested and Exercisable Options, Weighted Average Remaining Term	5 years 6 months 10 days
Range Two | Minimum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 28.88
Range Two | Maximum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 32.35
Range Three
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options (in shares)	415,356
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 40.14
Total Outstanding Options, Weighted Average Remaining Term	8 years 4 months 9 days
Vested and Exercisable Options (in shares)	85,766
Vested and Exercisable Options, Weighted Average Option Price per Share (in usd per share)	$ 41.80
Vested and Exercisable Options, Weighted Average Remaining Term	7 years 2 months 8 days
Range Three | Minimum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 38.05
Range Three | Maximum
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 41.95
Range Four
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options (in shares)	210,522
Total Outstanding Options, Weighted Average Option Price per Share (in usd per share)	$ 42.94
Total Outstanding Options, Weighted Average Remaining Term	8 years 3 months 19 days
Vested and Exercisable Options (in shares)	49,335
Vested and Exercisable Options, Weighted Average Option Price per Share (in usd per share)	$ 43.00
Vested and Exercisable Options, Weighted Average Remaining Term	8 years 2 months 8 days