Supplemental Balance Sheet, Income Statement and Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accrued liabilities
Accrued compensation	$ 177,707	$ 172,803
Deferred revenue	298,345	202,918
Other taxes payable	58,445	76,781
Workers' compensation liabilities	37,459	29,459
Interest payable	63,532	64,728
Warranty accrual	5,799	4,653
Litigation reserves	23,681	30,784
Current liability to discontinued operations	19,602	64,404
Professional fees	2,550	2,971
Current deferred tax liability	3,677	3,077
Current liability to acquisition of KVS	22,278	22,033
Other accrued liabilities	14,929	22,484
Accrued liabilities	$ 728,004	$ 697,093