Discontinued Operations (Narrative) (Details) (USD $)	1 Months Ended	0 Months Ended	12 Months Ended
	Nov. 24, 2010	Oct. 12, 2010	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Dividend received by shareholders without interest per share of common stock	$ 2.33
Maximum aggregate consideration per share		$ 2.33
Aggregate consideration approximate amount of cash received		$ 13,200,000
Aggregate principal amount of promissory notes		4,000,000
Purchases made prior to sale of business				1,100,000	3,000,000
Purchases made subsequent to sale of business			1,200,000	300,000
First Promissory Note [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate principal amount of promissory notes		1,400,000
Reduced value of promissory note in connection with purchase of certain products		800,000
Second Promissory Note [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate principal amount of promissory notes		2,600,000
Maturity of promissory note after determination of Ulticom's revenue				24-month period
Carrying value of promissory note			0	0
24-Month Period [Member] | Second Promissory Note [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of reduction				40.00%
Maximum revenue considered for reduction in the value of promissory note				75,000,000
Ulticom Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash dividend paid	64,100,000
Cash dividend per share paid	$ 5.74
Proceeds from dividend received by CTI	42,400,000
Proceeds from Divestiture of Businesses				17,200,000
Gain on Ulticom Sale, net of tax				2,927,000	(35,606,000)
Parent Company [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate consideration received			6,949,000	68,247,000	6,150,000
Parent Company [Member] | Ulticom Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses		17,200,000
Gain on Ulticom Sale, net of tax				$ 2,927,000	$ 0