Supplemental Balance Sheet, Income Statement and Cash Flow Information - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accrued liabilities
Accrued compensation	$ 106,864	$ 120,204
Deferred revenue	269,601	340,472
Other taxes payable	28,218	39,850
Workers' compensation liabilities	37,459	37,459
Interest payable	15,372	62,776
Litigation reserves	25,776	27,097
Current liability to discontinued operations	5,539	5,197
Current liability to acquisition of KVS	22,278	22,278
Other accrued liabilities	37,230	31,280
Accrued liabilities	$ 548,337	$ 686,613