Selected Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]
Revenue	$ 266,686,000		$ 295,732,000		$ 284,282,000		$ 276,272,000		$ 277,114,000		$ 277,916,000		$ 263,363,000		$ 269,466,000		$ 1,122,972,000		$ 1,087,859,000		$ 1,104,958,000
Gross profit	48,509,000		54,488,000		52,797,000		50,763,000		52,248,000		52,697,000		51,545,000		50,151,000		206,557,000		206,641,000		219,409,000
Operating and administrative expenses	45,052,000	[1]	46,006,000	[1]	46,107,000	[1]	45,708,000	[1]	42,717,000	[2],[3]	45,751,000	[2],[3]	46,303,000	[2],[3]	45,238,000	[2],[3]	182,873,000	[1]	180,009,000	[2],[3]	187,143,000
Restructuring and other related costs	3,573,000		0		(298,000)		370,000		5,716,000		0		0		0		3,645,000		5,716,000		0
Impairment of Intangible Assets, Finite-lived	3,800,000		0		0		0												1,236,000
Asset Impairment Charges	14,653,000																14,653,000		0		0
Operating profit (loss) (1)	(14,769,000)	[1]	8,482,000	[1]	6,988,000	[1]	4,685,000	[1]	3,815,000	[2],[3]	6,946,000	[2],[3]	5,242,000	[2],[3]	4,913,000	[2],[3]	5,386,000	[4],[5]	20,916,000	[2],[3],[4],[5]	32,266,000	[4],[5]
Income (loss) before income taxes	(14,790,000)		8,349,000		6,996,000		4,603,000		3,717,000		6,889,000		5,180,000		4,862,000		5,158,000		20,648,000		32,015,000
Net income	(8,917,000)		5,441,000		4,452,000		2,041,000		2,332,000		4,566,000		3,497,000		2,553,000		3,017,000		12,948,000		19,433,000
Net income attributable to CDI	(8,782,000)		5,400,000		4,427,000		2,037,000		2,427,000		4,528,000		3,438,000		2,491,000		3,082,000		12,884,000		19,116,000
Earnings per common share:
Basic (in dollars per share)	$ (0.45)		$ 0.28		$ 0.23		$ 0.10		$ 0.13		$ 0.23		$ 0.18		$ 0.13		$ 0.16		$ 0.66		$ 0.99
Diluted (in dollars per share)	$ (0.45)		$ 0.27		$ 0.22		$ 0.10		$ 0.12		$ 0.23		$ 0.17		$ 0.13		$ 0.16		$ 0.65		$ 0.97
Fair value of contingent consideration									600,000		500,000		400,000		300,000				600,000
Operating and Administrative Expenses [Member]
Earnings per common share:
CEO Compensation - Net Income	900,000
CEO Compensation - Net Income, Pre Tax	700,000
CEO Compensation - Net Income, Net of Tax	400,000
CEO Separation - DTA Write-off	500,000
Benefit related to settlement																			3,300,000
Year-End Adjustment [Member]
Selected Quarterly Financial Information [Abstract]
Asset Impairment Charges																	14,653,000
Earnings per common share:
Fair value of contingent consideration									$ 1,800,000										$ 1,800,000

[1] In In the first quarter of 2014, the Company recorded an aggregate $0.9 million charge to net income related to the separation of the Company's former CEO comprised of a $0.7 million pre-tax charge ($0.4 million after tax) to operations and an additional $0.5 million charge to income tax expense for the write-off of certain deferred tax assets related to the forfeiture of outstanding equity awards.

[2] In 2013, the Company's GETS segment recorded a $1.8 million benefit to "Operating and administrative expenses" related to the reduction of an acquisition earnout liability (by quarter: first $0.3 million, second $0.4 million, third $0.5 million and fourth $0.6 million.)

[3] In the fourth quarter of 2013, the Company recorded a $3.3 million benefit to "Operating and administrative expenses" related to the settlement of legal claims pursued by the Company.

[4] In 2014 and 2013, the Company recorded pre-tax charges of $3.6 million and $5.7 million, respectively, to "Restructuring and other related costs" related to the 2014 and 2013 Restructuring Plans. The following table summarizes the amount of restructuring and other related costs recognized by reporting segment for the indicated periods: Year ended December 31, 2014 2013 2012 GETS $2,244 $2,412 $—PSS 1,001 2,269 —MRI 259 313 —Corporate 141 722 —Restructuring and other related costs $3,645 $5,716 $—

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