Description of Business and Summary of Significant Accounting Policies - Fair Value Reporting (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Total assets measured at fair value	$ 32,453,000	$ 5,551,000
Total liabilities measured at fair value	0	10,095,000
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation:
Beginning balance	10,095,000	24,976,000
(Gains) or losses included in earnings	(3,105,000)	(16,543,000)
Reductions recorded against goodwill	0	0
Foreign currency translation adjustments	(537,000)	(260,000)
Business acquisitions	0	1,922,000
Settlements	(6,453,000)	0
Ending balance	0	10,095,000
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability, gain (loss) included in earnings, unrealized still held at year end	$ (3,105,000)	(16,543,000)
Derivative
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation:
Fair value Input, discount rate	12.60%
Contingent Accrued Earn-out Acquisition Consideration
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative liabilities	$ 0	10,095,000
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation:
Beginning balance	10,100,000
Ending balance	0	10,100,000
Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	32,072,000	4,493,000
Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	381,000	1,058,000
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Total assets measured at fair value	381,000	1,058,000
Total liabilities measured at fair value	0	0
Fair Value, Inputs, Level 1 | Contingent Accrued Earn-out Acquisition Consideration
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative liabilities	0	0
Fair Value, Inputs, Level 1 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	0	0
Fair Value, Inputs, Level 1 | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	381,000	1,058,000
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Total assets measured at fair value	32,072,000	4,493,000
Total liabilities measured at fair value	0	0
Fair Value, Inputs, Level 2 | Contingent Accrued Earn-out Acquisition Consideration
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative liabilities	0	0
Fair Value, Inputs, Level 2 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	32,072,000	4,493,000
Fair Value, Inputs, Level 2 | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	0	0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Total assets measured at fair value	0	0
Total liabilities measured at fair value	0	10,095,000
Fair Value, Inputs, Level 3 | Contingent Accrued Earn-out Acquisition Consideration
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Derivative liabilities	0	10,095,000
Fair Value, Inputs, Level 3 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	0	0
Fair Value, Inputs, Level 3 | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	0	0
Certificates of Deposit | Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale securities	$ 7,400,000	$ 50,000