Intangible Assets and Goodwill (Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite lived intangible assets
Gross Carrying Amount		$ 287,189		$ 287,199
Accumulated Amortization		(150,071)		(127,360)
Net Carrying Amount		137,118		159,839
Amortization expense	$ 8,000	23,000	$ 26,000
Customer relationships
Finite lived intangible assets
Gross Carrying Amount		268,189		268,199
Accumulated Amortization		(134,871)		(115,010)
Net Carrying Amount		133,318		153,189
Software & technology
Finite lived intangible assets
Gross Carrying Amount		19,000		19,000
Accumulated Amortization		(15,200)		(12,350)
Net Carrying Amount		$ 3,800		$ 6,650

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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