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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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Goodwill and Other Intangible Assets - Narrative (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Jul. 08, 2016
Goodwill [Line Items]
Goodwill	$ 69,727		$ 69,727	$ 69,727
Accumulated impairment	51,900		51,900	51,900
Goodwill and intangible asset impairment			0	0
Impairment charge related to other intangible assets			0	0
Amortization expense related to intangible assets	$ 18,900	$ 18,900	$ 25,200	$ 26,500
Array
Goodwill [Line Items]
Goodwill					$ 121,600