Shareholders' Equity and Common Stock Equivalents (Details 2) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options	747,032	669,693	634,437
Total Outstanding Options, Weighted Average Option Price per Share	$ 27.67	$ 24.00
Total Outstanding Options, Weighted Average Remaining Term	6 years 10 months 24 days
Vested and Exercisable Options	273,117	281,632
Vested and Exercisable Options, Weighted Average Option Price per Share	$ 22.73	$ 19.32	$ 17.20
Vested and Exercisable Options, Weighted Average Remaining Term	4 years 1 month 6 days
Minimum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 13.83
Maximum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 36.04
Exercise Price Range Range One [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options	176,688
Total Outstanding Options, Weighted Average Option Price per Share	$ 18.57
Total Outstanding Options, Weighted Average Remaining Term	2 years 3 months 18 days
Vested and Exercisable Options	157,029
Vested and Exercisable Options, Weighted Average Option Price per Share	$ 18.32
Vested and Exercisable Options, Weighted Average Remaining Term	2 years 3 months 18 days
Exercise Price Range Range One [Member] | Minimum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 13.83
Exercise Price Range Range One [Member] | Maximum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 20.75
Exercise Price Range Range Two [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options	450,674
Total Outstanding Options, Weighted Average Option Price per Share	$ 29.91
Total Outstanding Options, Weighted Average Remaining Term	8 years 2 months 12 days
Vested and Exercisable Options	87,832
Vested and Exercisable Options, Weighted Average Option Price per Share	$ 27.50
Vested and Exercisable Options, Weighted Average Remaining Term	6 years 2 months 12 days
Exercise Price Range Range Two [Member] | Minimum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 28.88
Exercise Price Range Range Two [Member] | Maximum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 31.13
Exercise Price Range Range Three [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Options	119,670
Total Outstanding Options, Weighted Average Option Price per Share	$ 32.67
Total Outstanding Options, Weighted Average Remaining Term	8 years 3 months 18 days
Vested and Exercisable Options	28,256
Vested and Exercisable Options, Weighted Average Option Price per Share	$ 32.39
Vested and Exercisable Options, Weighted Average Remaining Term	8 years 2 months 12 days
Exercise Price Range Range Three [Member] | Minimum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 32.35
Exercise Price Range Range Three [Member] | Maximum [Member]
Summary of options outstanding segregated by ranges of exercise prices
Total Outstanding Options, Weighted Average Option Price per Share	$ 36.04