Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue	$ 469,164	$ 383,940	$ 365,546
Reimbursable expenses	15,537	12,934	9,485
Total revenue	484,701	396,874	375,031
Direct client service costs
Compensation and benefits (includes $19,098, $17,086 and $14,891 of equity-based compensation for the years ended December 31, 2012, 2011 and 2010, respectively)	256,089	209,606	205,958
Other direct client service costs	13,119	9,048	7,548
Acquisition retention expenses (includes $2,908, $1,054 and $11 of equity-based compensation for the years ended December 31, 2012, 2011 and 2010, respectively)	9,536	1,624	11
Reimbursable expenses	15,734	13,073	9,547
Direct client service costs	294,478	233,351	223,064
Operating expenses
Selling, general and administrative (includes $3,531, $3,744 and $5,542 of equity-based compensation for the years ended December 31, 2012, 2011 and 2010, respectively)	116,032	100,624	97,451
Depreciation and amortization	18,138	11,164	9,916
Restructuring charges	1,796	4,090	0
Acquisition, integration and corporate development costs	6,865	2,372	704
Charge from impairment of certain intangible assets	0	0	674
Operating expenses	142,831	118,250	108,745
Operating income	47,392	45,273	43,222
Other expense/(income), net
Interest income	(59)	(77)	(112)
Interest expense	748	275	312
Other expense	380	1,505	173
Other expense/(income), net	1,069	1,703	373
Income before income taxes	46,323	43,570	42,849
Provision for income taxes	20,022	13,841	13,503
Net income	26,301	29,729	29,346
Net income attributable to noncontrolling interest	4,037	11,115	12,581
Net income attributable to Duff & Phelps Corporation	$ 22,264	$ 18,614	$ 16,765
Common Stock Class A [Member]
Weighted average shares of Class A common stock outstanding
Weighted average shares of Class A common stock outstanding, basic	33,267	26,958	25,170
Weighted average shares of Class A common stock outstanding, diluted	34,585	27,832	26,089
Net income per share attributable to stockholders of Class A common stock of Duff & Phelps Corporation
Earnings per share, basic	$ 0.64	$ 0.65	$ 0.62
Earnings per share, diluted	$ 0.62	$ 0.63	$ 0.60
Cash dividends declared per common share	$ 0.36	$ 0.32	$ 0.23