(Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Accounts receivable, billed		$ 312,940	$ 476,903
Effect of change, accounts receivable		(163,963)
Unbilled accounts receivable, current, adjusted			0
Effect of change, contract assets		171,956
Contract assets, current	$ 256,201	171,956
Accounts Receivable, Net, Current	625,086	484,896	476,903
Effect of change, total accounts receivable		7,993
Inventory, Net	194,507		215,282
Effect of change, inventory		(34,187)
Inventory, Gross		181,095
Accrued Liabilities, Current	392,105	324,803	350,258
Effect of change, total accrued liabilities		(25,455)
Effect of change, accrued liabilities		(63,045)
Accrued liabilities, (excl deferred revenue) adjusted		287,213
Contract with Customer, Liability	85,172	37,590	0
Effect of change, deferred revenue		37,590
Deferred Revenue		37,590
Other Long-term Debt, Noncurrent			131,323
Effect of change, other long -term liabilities		(202)
Other Long-term Debt		131,121
Retained Earnings (Accumulated Deficit)	$ 2,204,548	2,416,875	$ 2,417,412
Cumulative Effect on Retained Earnings, Net of Tax		$ (537)