Retirement And Other Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Employer contributions to defined contribution plan	$ 3,100	$ 2,500	$ 1,800
Other long-term liabilities	37,335	35,509
Accrued expenses and other current liabilities	$ 21,554	19,002
Deferred Compensation, Percentage Of Funds Invested	60.00%
Deferred Compensation
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Compensation deferred by participants	$ 2,300	1,200	1,600
Amount withdrawn from the Plan by participants	1,500	800	$ 400
Other long-term liabilities	13,400	11,700
Accrued expenses and other current liabilities	200	200
Other Assets	$ 8,200	$ 7,800