Stock Option and Compensation Plans - Options Outstanding and Exercisable by Exercise Price and Options Exercised (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Options Outstanding
Total Options Outstanding (in shares) | shares	3,999
Weighted Average Remaining Life (Years)	7 years 11 months 3 days
Weighted Average Exercise Price (in dollars per share)	$ 29.76
Aggregate Intrinsic Value of Options Outstanding | $	$ 141
Options Exercisable
Number Exercisable (in shares) | shares	1,848
Weighted Average Exercise Price (in dollars per share)	$ 34.15
Aggregate Intrinsic Value of Options Exercisable | $	$ 141
$0.12-$10.03
Options Outstanding
Total Options Outstanding (in shares) | shares	1,255
Weighted Average Remaining Life (Years)	9 years 1 month 30 days
Weighted Average Exercise Price (in dollars per share)	$ 4.89
Options Exercisable
Number Exercisable (in shares) | shares	163
Weighted Average Exercise Price (in dollars per share)	$ 7.06
Exercise prices, low end of range (in dollars per share)	0.12
Exercise prices, high end of range (in dollars per share)	$ 10.03
$10.04-$20.00
Options Outstanding
Total Options Outstanding (in shares) | shares	260
Weighted Average Remaining Life (Years)	6 years 2 months 26 days
Weighted Average Exercise Price (in dollars per share)	$ 13.45
Options Exercisable
Number Exercisable (in shares) | shares	191
Weighted Average Exercise Price (in dollars per share)	$ 13.49
Exercise prices, low end of range (in dollars per share)	10.04
Exercise prices, high end of range (in dollars per share)	$ 20.00
$20.01-$30.00
Options Outstanding
Total Options Outstanding (in shares) | shares	150
Weighted Average Remaining Life (Years)	6 years 7 months 8 days
Weighted Average Exercise Price (in dollars per share)	$ 25.51
Options Exercisable
Number Exercisable (in shares) | shares	125
Weighted Average Exercise Price (in dollars per share)	$ 25.55
Exercise prices, low end of range (in dollars per share)	20.01
Exercise prices, high end of range (in dollars per share)	$ 30.00
$30.01-$40.00
Options Outstanding
Total Options Outstanding (in shares) | shares	1,031
Weighted Average Remaining Life (Years)	6 years 4 months 23 days
Weighted Average Exercise Price (in dollars per share)	$ 32.67
Options Exercisable
Number Exercisable (in shares) | shares	828
Weighted Average Exercise Price (in dollars per share)	$ 32.88
Exercise prices, low end of range (in dollars per share)	30.01
Exercise prices, high end of range (in dollars per share)	$ 40.00
$40.01-$55.00
Options Outstanding
Total Options Outstanding (in shares) | shares	839
Weighted Average Remaining Life (Years)	8 years 2 months 30 days
Weighted Average Exercise Price (in dollars per share)	$ 46.29
Options Exercisable
Number Exercisable (in shares) | shares	371
Weighted Average Exercise Price (in dollars per share)	$ 45.51
Exercise prices, low end of range (in dollars per share)	40.01
Exercise prices, high end of range (in dollars per share)	$ 55.00
$55.01-$73.22
Options Outstanding
Total Options Outstanding (in shares) | shares	464
Weighted Average Remaining Life (Years)	8 years 9 months 20 days
Weighted Average Exercise Price (in dollars per share)	$ 71.20
Options Exercisable
Number Exercisable (in shares) | shares	170
Weighted Average Exercise Price (in dollars per share)	$ 71.15
Exercise prices, low end of range (in dollars per share)	55.01
Exercise prices, high end of range (in dollars per share)	$ 73.22