Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 29, 2013
Deferred Tax Asset:
State taxes	$ 1,746	$ 2,635
Reserves and contingent liabilities	3,842	8,860
Allowance for doubtful accounts	4,115	6,084
Accrued liabilities	19,404	12,212
Stock-based compensation	10,516	10,273
Intangibles	2,910	1,159
Loss carry-forwards	5,512	10,815
Valuation allowance	(7,791)	(7,576)
Total deferred tax asset	40,254	44,462
Deferred Tax Liability:
Unbilled revenue	(46,513)	(49,150)
Prepaid expense	(5,506)	(5,834)
Intangibles	(33,068)	(30,416)
Property and equipment	(10,713)	(8,235)
Total deferred tax liability	(95,800)	(93,635)
Net deferred tax liability	(55,546)	(49,173)
Undistributed earnings of foreign subsidiaries	60,000
Incremental federal tax due to repatriation of foreign earnings	5,100
Unrecognized tax benefits that would affect the effective tax rate, if recognized	$ 21,600
Period during which unrecognized tax benefits would affect the effective tax rate	12 months
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Beginning balance	$ 21,717	25,886	$ 24,092
Additions for current year tax positions	1,147	1,243	2,661
Additions for prior year tax positions	2,309	1,416	4,951
Reductions for prior year tax positions	(23)		(5,818)
Settlements	(3,532)	(6,828)
Ending balance	21,618	21,717	$ 25,886
Accrued additional interest	400	200
Reduction in accrued interest	500	900
Amount of interest and penalties accrued	1,200	$ 1,400
Foreign
Deferred Tax Liability:
Net operating loss carry forwards which expire at various dates	18,400
Net operating loss carry forwards which have no expiration date	4,400
Expiration dates through 2035 | State
Deferred Tax Liability:
Net operating loss carry forwards which expire at various dates	38,400
Expiration dates through 2035 | Foreign
Deferred Tax Liability:
Net operating loss carry forwards which expire at various dates	$ 14,000