Consolidated Statements of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Income [Abstract]
Gross Revenue	$ 937,133	$ 840,775	$ 764,734
Direct Costs	583,195	520,522	476,187
Operating costs and expenses
Indirect and selling expenses	263,878	240,964	218,526
Depreciation and amortization	10,351	10,757	10,775
Amortization of intangible assets	14,089	9,550	12,326
Total operating costs and expenses	288,318	261,271	241,627
Operating Income	65,620	58,982	46,920
Interest expense	(3,384)	(2,248)	(3,403)
Other income (expense)	(325)	26	165
Income Before Income Taxes	61,911	56,760	43,682
Provision for Income Taxes	23,836	21,895	16,511
Net Income	38,075	34,865	27,171
Earnings per Share:
Basic	$ 1.94	$ 1.77	$ 1.40
Diluted	$ 1.91	$ 1.75	$ 1.38
Weighted-average Common Shares Outstanding:
Basic	19,663	19,684	19,375
Diluted	19,957	19,928	19,626
Other comprehensive income:
Foreign currency translation adjustments	(436)	(281)	(187)
Comprehensive income	$ 37,639	$ 34,584	$ 26,984