Lease Commitments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 28, 2014	Dec. 29, 2013	Dec. 30, 2012
Leases [Abstract]
Sublease income on operating leases	$ 4.5
Capital Leases
2015	0.1
2016	0
2017	0
2018	0
2019	0
Thereafter	0
Total future minimum lease payments	0.1
Less amount representing interest	0
Present value of capital lease obligations	0.1us-gaap_CapitalLeaseObligations
Less current portion	0.1us-gaap_CapitalLeaseObligationsCurrent	0.3us-gaap_CapitalLeaseObligationsCurrent
Capital lease obligations, net of current portion	0	0.1
Operating Leases
2015	20.2
2016	17.2
2017	15.1
2018	12.7
2019	10.5
Thereafter	9.1
Total future minimum lease payments	84.8
Capital Leased Assets [Line Items]
Property under capital leases by major class, gross	0.4us-gaap_CapitalLeasedAssetsGross	1.9us-gaap_CapitalLeasedAssetsGross
Less: Accumulated amortization	0.4	1.7
Property under capital leases by major class, net	0	0.2
Amortization expense related to capital leases	0.2	0.2	0.1
Gross rent expense under operating leases	25.1	20.9	21.1
Sublease income	3.3	2.3	2.7
Accrual for Unused Facilities [Roll Forward]
Accrual for excess facilities - beginning balance	12.4ktos_AccrualForUnusedFacilities	18.7ktos_AccrualForUnusedFacilities
Adjustment of excess facility accrual	0.2	(4.7)
Cash payments	(1.3)	(1.6)
Accrual for excess facilities - ending balance	11.3ktos_AccrualForUnusedFacilities	12.4ktos_AccrualForUnusedFacilities	18.7ktos_AccrualForUnusedFacilities
Deferred rent	5.3us-gaap_DeferredRentCredit	3.2us-gaap_DeferredRentCredit	1.3us-gaap_DeferredRentCredit
Facilities
Capital Leased Assets [Line Items]
Property under capital leases by major class, gross	0	1.0
Vehicles
Capital Leased Assets [Line Items]
Property under capital leases by major class, gross	0.3	0.5
Office equipment
Capital Leased Assets [Line Items]
Property under capital leases by major class, gross	$ 0.1	$ 0.4

Accrual for Unused Facilities

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Accrual for Unused Facilities, Accrual Adjustment

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Accrual for Unused Facilities, Cash Payments

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Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Amount of capital lease obligation due within one year or the normal operating cycle, if longer.

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The total gross amount less the charge for the use of the long-lived depreciable assets subject to a lease meeting the criteria for capitalization.

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Amount of minimum lease payments for capital leases.

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Amount of minimum lease payments for capital leases due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount necessary to reduce net minimum lease payments to present value for capital leases.

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The charge for the use of long-lived depreciable capital leased assets for the period.

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The total charge for the use of long-lived depreciable assets subject to a lease meeting the criteria for capitalization.

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The cumulative difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property by the lessor or lessee, respectively.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Contractually required future rental payments receivable on noncancelable subleasing arrangements.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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This element represents the payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease, excluding contingent rentals and a guarantee by the lessee of the lessor's debt and the lessee's obligation to pay (apart from the rental payments) executory costs such as insurance, maintenance, and taxes.

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The total amount of sublease rental income recognized during the period that reduces the entity's rent expense incurred under operating leases.

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