Stock-based Compensation Employee Service Share-based Compensation, Allocation of Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	$ 21,279	$ 20,470	$ 20,526
Cost of services and sales, exclusive of depreciation [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	10,126	10,331	10,268
General and Adminstrative Expense, exclusive of depreciation [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	$ 11,153	$ 10,139	$ 10,258