Summary Of Major Accounting Policies Summary of Major Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable, billed	$ 300,976
Revenues	416,413	$ 484,175	$ 446,176
Revenue, adjusted	422,477
effect of change, revenue	6,064
Cost of Goods and Services Sold	397,585		401,321
Cost of services and products, adjusted	406,697
Effect of change, cost of services and products	9,112
Income Tax Expense (Benefit)	5,888		(1,083)
Income taxes, adjusted	5,234
Effect of change, income taxes	(654)
Accounts Receivable, Net, Current	471,345	476,903
Effect of change, total accounts receivable	(8,996)			$ 7,993
Effect of change, accounts receivable	0			(163,963)
Total accounts receivable, adjusted	462,349			484,896
Accounts receivable, adjusted	300,976			312,940
Inventory, Net	185,009	215,282
Inventory, adjusted	209,776			181,095
Accrued liabilities, excluding deferred revenue	258,975
Unbilled Receivables, Current	170,369	0		171,956
Unbilled accounts receivable, current, adjusted	161,373
Effect of change, unbilled accounts receivable	(8,996)
Inventory, Gross		215,282
Accrued Liabilities, Current	289,527	350,258
Accrued liabilities, (excl deferred revenue) adjusted	258,803			287,213
Total accrued liabilities, adjusted	307,607			324,803
Effect of change, accrued liabilities	(172)			(63,045)
Effect of change, total accrued liabilities	18,080			(25,455)
Deferred Revenue	30,552	0		37,590
Effect of change, deferred revenue	18,252
Deferred revenue without adoption of ASC 606	48,804
Effect of change, inventory	24,767			(34,187)
Other Liabilities, Noncurrent	132,888	131,323
Other long-term liabilities, adjusted	132,436			131,121
Effect of change, other long -term liabilities	(452)			(202)
Retained Earnings (Accumulated Deficit)	2,367,742	$ 2,417,412		2,416,875
Effect of change, retained earnings	(1,857)			$ (537)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(49,133)		$ (7,534)
Effect of change, Net Income	(2,394)
Retained earnings, adjusted	2,365,885
Net income, adjusted	$ (51,527)