Restricted Cash (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Restricted Cash Abstract]
Cash and cash equivalents	$ 141,393	$ 155,750	$ 181,833	$ 123,524
Restricted cash included in other current assets	0	82	62	353
Restricted cash included in other assets	0	18,901	0	19,678
Cash cash equivalents restricted cash and restricted cash equivalents	$ 141,393	174,733	181,895	$ 143,555
Loss Contingency, Settlement Agreement, Terms	Prior to December 2020, the Company had restricted cash recorded in other assets related to proceeds from an inactive subsidiary of the Company which previously executed separate settlement and release agreements with two of its insurance carriers for an original total value of $35.0 million.
Proceeds Of Settlement And Release Agreements			$ 35,000
Payments Of Settlement and Release Agreements		800
Interest Income Other		$ 100