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Share-Based Payments - Narrative (Details) - USD ($) | 12 Months Ended | 18 Months Ended | 30 Months Ended
--- | --- | --- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Jun. 30, 2019 | Dec. 31, 2021
Restricted Stock Awards |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award cliff vesting period | 4 years |  |  |  |
Granted (in dollars per share) | $ 43.55 | $ 45.97 | $ 48.18 |  |
Fair value of awards vested | $ 2,100,000 | $ 2,800,000 | $ 2,400,000 |  |
Unrecognized compensation costs | $ 2,400,000 |  |  |  | $ 2,400,000
Unrecognized compensation costs, period of recognition | 1 year 9 months 29 days |  |  |  |
Restricted Stock Awards | Minimum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period | 3 years |  |  |  |
Restricted Stock Awards | Maximum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period | 4 years |  |  |  |
Stock Performance Awards |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period | 3 years |  |  |  |
Granted (in dollars per share) | $ 38.34 | $ 47.79 | $ 42.87 |  |
Fair value of awards vested | $ 2,500,000 | $ 3,400,000 | $ 6,100,000 |  |
Unrecognized compensation costs | $ 400,000 |  |  |  | $ 400,000
Unrecognized compensation costs, period of recognition | 1 year 2 months 8 days |  |  |  |
Stock Performance Awards | Minimum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Percentage of target amount as actual payment | 0.00% |  |  |  |
Stock Performance Awards | Maximum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Percentage of target amount as actual payment | 150.00% |  |  |  |
The 1999 Employee Stock Purchase Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share-based payment awards, number of shares authorized (in shares) | 1,400,000 |  |  |  | 1,400,000
Discount from market price rate (as a percent) | 15.00% |  |  | 100.00% | 85.00%
Maximum number of shares available to be purchased per participant (in shares) | 2,000 |  |  |  |
Purchase period | 6 months |  |  |  |
Maximum employee subscription amount | $ 25,000 |  |  |  |
Shares holding period | 18 months |  |  |  |
Share-based payment arrangement, expense | $ 200,000 | $ 200,000 | $ 100,000 |  |
Shares issued under the plan (in shares) | 27,975 | 31,661 | 17,104 |  |
Number of shares available for grant (in shares) | 290,127 |  |  |  | 290,127
The 1999 Employee Stock Purchase Plan | Minimum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Employee monthly withholding amounts | $ 10 |  |  |  |
The 1999 Employee Stock Purchase Plan | Maximum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Employee monthly withholding amounts | $ 2,000 |  |  |  |
The 2014 Stock Incentive Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share-based payment awards, number of shares authorized (in shares) | 1,900,000 |  |  |  | 1,900,000
Share-based payment arrangement, expense | $ 6,700,000 | $ 6,100,000 | $ 5,900,000 |  |
Number of shares available for grant (in shares) | 722,200,000 |  |  |  | 722,200,000
Share-based payment arrangement, expense, tax benefit | $ 1,800,000 | $ 2,100,000 | $ 2,300,000 |  |

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- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued 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). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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