Fixed Assets (Summary Of Fixed Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Office equipment	$ 356,707	$ 341,641
Leasehold improvements	141,585	129,279
Internally developed software	85,993	67,250
Building	80,771	73,549
Aircraft engine operating leases	2,370	8,612
Fixed assets, gross	667,426	620,331
Accumulated depreciation and amortization	(475,898)	(420,288)
Fixed assets, net	$ 191,528	$ 200,043

Accumulated depreciation depletion and amortization fixed assets excluding leased assets.

No definition available.

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- Definition

Fixed assets gross excluding leased assets.

+ References

No definition available.

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- Definition

Fixed assets net excluding leased assets.

+ References

No definition available.

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- Definition

Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482099/360-10-50-1

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- Definition

Amount before accumulated amortization of capitalized costs for computer software, including but not limited to, acquired and internally developed computer software.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 985
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481283/985-20-50-1

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- Definition

Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

+ References

+ Details

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- Definition

Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

+ References

+ Details

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- References

No definition available.

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- Definition

Amount, before accumulated depreciation, of lessor's underlying asset for which right to use has been conveyed to lessee under operating lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 840
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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