Reporting Segments (Details) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Restructuring Charges	$ 47,000us-gaap_RestructuringCharges	$ 370,000us-gaap_RestructuringCharges
Revenue	257,458,000us-gaap_Revenues	276,272,000us-gaap_Revenues
Gross profit	46,770,000us-gaap_GrossProfit	50,763,000us-gaap_GrossProfit
Operating profit	1,140,000us-gaap_OperatingIncomeLoss	4,685,000us-gaap_OperatingIncomeLoss
Other income (expense), net	13,000us-gaap_OtherNonoperatingIncomeExpense	(82,000)us-gaap_OtherNonoperatingIncomeExpense
Assets	375,719,000us-gaap_Assets		372,220,000us-gaap_Assets
Income before income taxes	1,153,000	4,603,000
CEO Compensation - Net Income		900,000cdi_CEOCompensationNetIncome
CEO Compensation - Operating Charge		700,000cdi_CEOCompensationOperatingCharge
CEO Compensation - Operating Charge (after Tax)		400,000
CEO Separation - DTA Write-off		500,000cdi_CEOSeparationDTAWriteoff
GETS [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	0	333,000
Revenue	82,521,000	82,254,000
Gross profit	20,942,000	22,400,000
Operating profit	348,000	1,556,000
Assets	120,552,000		120,223,000
PSS [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	47,000	37,000
Revenue	161,426,000	180,139,000
Gross profit	19,259,000	21,946,000
Operating profit	4,156,000	6,145,000
Assets	166,596,000		159,774,000
MRI [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	0	0
Revenue	13,511,000	13,879,000
Gross profit	6,569,000	6,417,000
Operating profit	1,456,000	1,260,000
Assets	23,260,000		23,539,000
Corporate [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	0	0
Operating profit	(4,820,000)	(4,276,000)
Assets	$ 65,311,000		$ 68,684,000

CEO Compensation - Net Income: Net Income impact of CEO separation cost

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CEO Compensation - Operating Charge: CEO pre-tax compensation change to operations

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CEO Compensation - Operating Charge (after Tax): : CEO after-tax compensation change to operations

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CEO Separation - DTA Write-off: Charge to income tax expense for the write-off of deferred tax assets related to the forfeiture of outstanding awards

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No definition available.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

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The net result for the period of deducting operating expenses from operating revenues.

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The net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income (expense) recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) net gains or losses on securities, (d) unusual costs, (e) gains or losses on foreign exchange transactions, and (f) miscellaneous other income and expense items.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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