Segment Information (Long-lived Assets by Geographic Location) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Property and equipment, net	$ 218,699	$ 256,045
United States
Segment Reporting Information [Line Items]
Property and equipment, net	203,635	239,387
Europe
Segment Reporting Information [Line Items]
Property and equipment, net	14,392	15,938
Other
Segment Reporting Information [Line Items]
Property and equipment, net	$ 672	$ 720

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant