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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Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Impairment of goodwill	$ 0		$ 0	$ 16,400,000	$ 0	$ 0
Amortization of acquired intangibles	1,600,000		$ 1,600,000	$ 5,100,000	4,900,000
Impairment of definite and indefinite-lived intangible assets	0					$ 0
Minimum
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period				3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period				9 years
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Additions				$ 0	0
Trade Names
Finite-Lived Intangible Assets [Line Items]
Additions				1,000,000.0	$ 1,000,000.0
Copper Rock
Finite-Lived Intangible Assets [Line Items]
Impairment of goodwill	$ 0	$ 16,400,000		$ 16,400,000