Income Taxes - Summary of reconciliation between federal statutory rate and effective tax rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes
Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	2.90%	1.50%	(0.30%)
Foreign taxes, net of federal benefit	5.10%	(0.40%)	(0.20%)
Tax credits	(3.50%)	0.10%	0.30%
Change in contingencies	8.60%
Non-deductible expenses	(2.80%)	(0.10%)	(1.90%)
Adjustments related to CARES Act	3.20%	8.50%
Change in estimated deferred rate	10.20%
Adjustments related to vesting of restricted stock	7.10%	(0.80%)	(0.40%)
Other	4.30%	1.60%	4.50%
Effective tax rate	56.10%	31.40%	23.00%