Cash Option Profit Sharing Plan and Trust (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items]
Contributions to 401(k) cash option profit sharing plan	$ 508	$ 557	$ 536
Foreign Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, maximum annual contributions per employee, percent	12.00%
Contributions to 401(k) cash option profit sharing plan	$ 2,600	$ 4,200	$ 4,000
Maximum
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	100.00%
Defined contribution plan, maximum annual contributions per employee, percent	1.00%
Minimum
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	50.00%
Defined contribution plan, maximum annual contributions per employee, percent	2.00%