Retirement And Other Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Employer contributions to defined contribution plan	$ 7,700	$ 6,800	$ 4,200
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Other long-term liabilities	62,171	58,027
Accrued expenses and other current liabilities	$ 42,781	26,424
Deferred compensation, percentage of funds invested	99.00%
Deferred Compensation
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Compensation deferred by participants	$ 900	6,900	4,900
Amount withdrawn from the Plan by participants	1,700	200	$ 200
Other long-term liabilities	30,300	25,900
Accrued expenses and other current liabilities	200	400
Life insurance contract assets	$ 30,100	$ 22,200