Employee Benefit Plans (Employee Benefits Charged To Operating Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total employee benefits	$ 67,376	$ 66,470	$ 60,180
Payroll Taxes [Member]
Total employee benefits	24,402	23,210	22,235
Medical Plans [Member]
Total employee benefits	25,143	25,497	20,659
401K Plan [Member]
Total employee benefits	14,244	13,562	12,841
Pension Plans [Member]
Total employee benefits	704	987	1,495
Other [Member]
Total employee benefits	$ 2,883	$ 3,214	$ 2,950