Stock-Based Compensation - Narrative (Details)	12 Months Ended
Dec. 31, 2020 USD ($) plan $ / shares shares	Dec. 31, 2019 $ / shares shares	Dec. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under the 2016 Plan (in shares)	2,761,911
Unrecognized compensation expense for all nonvested awards \| $	$ 31,700,000
Weighted average period for recognition	1 year 7 months 6 days
Cash-settled SARs, outstanding (in shares)	24,051
Stock-settled SARs, outstanding (in shares)	3,628
Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reduced for each award granted (in shares)	1
Awards, expiration period	10 years
Award Types Other than Stock Options and Stock Appreciation Rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reduced for each award granted (in shares)	2.5
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards, expiration period	10 years
Vesting period	4 years
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under the 2016 Plan (in shares)	3,793,218
Percentage of current market price for sales to eligible employees	85.00%
Limitation on payroll deductions of employee's base salary, percent	25.00%
Limitation on payroll deductions of employee's base salary, amount \| $	$ 25,000
Maximum number of shares per employee (in shares)	2,000
Maximum number of shares per employee, per year (in shares)	8,000
Purchases of shares (in shares)	36,494	51,391	55,669
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted at target level (in shares)	8,721	13,308	15,942
Granted at target level (in dollars per share) \| $ / shares	$ 200.35	$ 116.39	$ 96.77
Annual Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Granted at target level (in shares)	350	1,300	1,500
Granted at target level (in dollars per share) \| $ / shares	$ 156.49	$ 106.14	$ 93.00
Conversion rate	0.25
Share-based compensation arrangement by share-based payment award, equity instruments other than options, forfeited in period (in shares)	0	0	200
Stock-settled PSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted at target level (in shares)	53,659	84,309	102,307
Granted at target level (in dollars per share) \| $ / shares	$ 177.31	$ 103.40	$ 90.45
Share-based compensation arrangement by share-based payment award, equity instruments other than options, forfeited in period (in shares)	11,404	16,204	23,946
Deferred Compensation, Share-based Payments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation conversion unit (in shares)	1
Number of deferred compensation plans \| plan	2
Number of deferred stock units (in shares)	358,890
Number of deferred stock units payable in cash (in shares)	6,274
Deferred Compensation, Share-based Payments \| Non-Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted at target level (in shares)	10,302
Granted at target level (in dollars per share) \| $ / shares	$ 194.29

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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The highest quantity of shares an employee can purchase under the plan per period.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Purchase price of common stock expressed as a percentage of its fair value.

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Reduction In Number Of Shares Available For Grant For Each Award Granted

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Number of stock-settled stock appreciation rights outstanding.

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