Summary of Significant Accounting Policies - Reconciliation of Restructuring Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Charged to restructuring costs	$ 900	$ 2,300	$ 2,300	$ 600	$ 700	$ 1,600	$ 1,200	$ 6,052	$ 3,571	$ 2,758
Employee Termination Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period				386			556	386	556	87
Charged to restructuring costs								2,525	1,870	1,600
Payments								(2,412)	(2,040)	(1,131)
Balance at end of period	499				386			499	386	556
Lease-Related Exit Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period				$ 1,223			127	1,223	127
Charged to restructuring costs								2,190	1,311
Payments								(726)	(215)
Balance at end of period	$ 2,687				$ 1,223			2,687	1,223	127
Lease-Related Exit Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period							$ 390		390	441
Charged to restructuring costs										184
Payments										(235)
Balance at end of period										390
Other costs
Restructuring Reserve [Roll Forward]
Charged to restructuring costs								0	0	500
Strategic Reduction Of Real Estate Footprint
Restructuring Reserve [Roll Forward]
Charged to restructuring costs								1,100	$ 200	$ 400
Legal Entity Reorganization
Restructuring Reserve [Roll Forward]
Charged to restructuring costs								$ 200