Stock Plans - Summary of Restricted Stock and Unit Activity (Details)	9 Months Ended
	Sep. 30, 2020 $ / shares shares
Performance Shares
Shares
Unvested, beginning balance (in shares) | shares	238,035
Granted (in shares) | shares	65,982
Vested (in shares) | shares	(132,036)
Forfeited (in shares) | shares	(3,698)
Unvested, ending balance (in shares) | shares	201,782
Weighted Average Exercise Price (dollars per share)
Unvested, beginning balance (dollars per share) | $ / shares	$ 85.39
Granted (dollars per share) | $ / shares	127.33
Vested (dollars per share) | $ / shares	73.00
Forfeited (dollars per share) | $ / shares	120.69
Unvested, ending Balance (dollars per share) | $ / shares	$ 104.41
Restricted Stock Activity
Shares
Unvested, beginning balance (in shares) | shares	172,701
Granted (in shares) | shares	48,138
Vested (in shares) | shares	(63,104)
Forfeited (in shares) | shares	(5,081)
Unvested, ending balance (in shares) | shares	152,654
Weighted Average Exercise Price (dollars per share)
Unvested, beginning balance (dollars per share) | $ / shares	$ 90.38
Granted (dollars per share) | $ / shares	122.69
Vested (dollars per share) | $ / shares	81.56
Forfeited (dollars per share) | $ / shares	104.53
Unvested, ending Balance (dollars per share) | $ / shares	$ 103.75