Commitments and Contingencies (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Other Commitments [Line Items]
Unemployment benefits, possible liability with a change in control	$ 45,000
Unemployment benefits, possible liability without a change in control	17,300
Maximum potential capital contributions	22,500
Equity method investment	(7,000)	$ (2,500)
Operating lease not yet commenced, future lease payments	$ 10,900
Operating lease not yet commenced, term of contract	129 months
Operating lease, advances for leasehold improvements	$ 1,600
WorkLLama
Other Commitments [Line Items]
Equity method investment	$ (7,000)		$ (4,000)
Minimum
Other Commitments [Line Items]
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	6 months
Severance payment if agreement terminated meeting specific criteria, percentage of annual bonus	50.00%
Severance payment if agreement terminated meeting specific criteria, percentage of annual salary	100.00%
Renewal terms of current operating leases	1 year
Maximum
Other Commitments [Line Items]
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	3 years
Severance payment if agreement terminated meeting specific criteria, percentage of annual bonus	300.00%
Severance payment if agreement terminated meeting specific criteria, percentage of annual salary	300.00%
Renewal terms of current operating leases	5 years