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 - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Goodwill [Line Items]
Amortization of intangible asset	$ 0.1	$ 0.1
Intangible Assets	6.3		$ 6.3
Accumulated Amortization	1.2		1.1
Commercial [Member]
Goodwill [Line Items]
Goodwill			$ 54.3
Residential [Member]
Goodwill [Line Items]
Goodwill	$ 14.2
Domain Names [Member]
Goodwill [Line Items]
Amortization period	15 years