Retirement And Other Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Employer contributions to defined contribution plan	$ 9,000	$ 7,700	$ 6,800
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Other long-term liabilities	116,353	62,171
Accrued expenses and other current liabilities	$ 69,524	42,781
Deferred compensation, percentage of funds invested	99.00%
Wage inflation	2.00%
Next fiscal year minimum funding requirements	$ 1,300
Minimum
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Wage inflation	0.00%
Maximum
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Wage inflation	2.00%
Deferred Compensation
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Compensation deferred by participants	$ 2,900	900	6,900
Amount withdrawn from the Plan by participants	200	1,700	$ 200
Other long-term liabilities	38,500	30,300
Accrued expenses and other current liabilities	200	200
Life insurance contract assets	$ 35,300	$ 30,100