Stock-Based Compensation - Summary Stock Options Outstanding and Exercisable (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding (in shares) | shares	71,594
Options outstanding, weighted average remaining contractual life	4 years 7 months 9 days
Weighted average exercise price (in dollars per share)	$ 74.54
Options exercisable (in shares) | shares	71,594
Options exercisable, weighted average exercise price (in dollars per share)	$ 74.54
$47.50 - $47.50
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	47.50
Exercise price range, upper limit (in dollars per share)	$ 47.50
Options outstanding (in shares) | shares	2,700
Options outstanding, weighted average remaining contractual life	3 years 1 month 17 days
Weighted average exercise price (in dollars per share)	$ 47.50
Options exercisable (in shares) | shares	2,700
Options exercisable, weighted average exercise price (in dollars per share)	$ 47.50
$65.36 - $65.36
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	65.36
Exercise price range, upper limit (in dollars per share)	$ 65.36
Options outstanding (in shares) | shares	1,582
Options outstanding, weighted average remaining contractual life	4 years 1 month 24 days
Weighted average exercise price (in dollars per share)	$ 65.36
Options exercisable (in shares) | shares	1,582
Options exercisable, weighted average exercise price (in dollars per share)	$ 65.36
$65.45 - $65.45
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	65.45
Exercise price range, upper limit (in dollars per share)	$ 65.45
Options outstanding (in shares) | shares	2,900
Options outstanding, weighted average remaining contractual life	4 years 1 month 17 days
Weighted average exercise price (in dollars per share)	$ 65.45
Options exercisable (in shares) | shares	2,900
Options exercisable, weighted average exercise price (in dollars per share)	$ 65.45
$73.52 - $73.52
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	73.52
Exercise price range, upper limit (in dollars per share)	$ 73.52
Options outstanding (in shares) | shares	50,000
Options outstanding, weighted average remaining contractual life	4 years 6 months 29 days
Weighted average exercise price (in dollars per share)	$ 73.52
Options exercisable (in shares) | shares	50,000
Options exercisable, weighted average exercise price (in dollars per share)	$ 73.52
$85.99 - $85.99
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	85.99
Exercise price range, upper limit (in dollars per share)	$ 85.99
Options outstanding (in shares) | shares	14,412
Options outstanding, weighted average remaining contractual life	5 years 1 month 24 days
Weighted average exercise price (in dollars per share)	$ 85.99
Options exercisable (in shares) | shares	14,412
Options exercisable, weighted average exercise price (in dollars per share)	$ 85.99