Supplemental Balance Sheet, Income Statement and Cash Flow Information (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accrued liabilities
Accrued compensation	$ 151,812	$ 177,707
Deferred revenue	360,513	298,345
Other taxes payable	42,175	58,445
Workers' compensation liabilities	37,459	37,459
Interest payable	17,708	63,532
Litigation reserves	25,998	23,681
Current liability to discontinued operations	5,885	19,602
Current deferred tax liability	3,677	3,677
Current liability to acquisition of KVS	22,278	22,278
Share repurchase	33,421
Other accrued liabilities	29,883	23,278
Accrued liabilities	$ 730,809	$ 728,004