Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016
Revenues:
Revenues before reimbursements	$ 82,359	$ 74,160	$ 246,946	$ 226,444
Reimbursements	5,196	3,452	12,571	11,619
Revenues	87,555	77,612	259,517	238,063
Operating expenses:
Compensation and related expenses	51,493	47,797	157,447	146,854
Other operating expenses	7,500	7,020	21,966	21,221
Reimbursable expenses	5,196	3,452	12,571	11,619
General and administrative expenses	4,061	3,748	13,277	11,407
Total operating expenses	68,250	62,017	205,261	191,101
Operating income	19,305	15,595	54,256	46,962
Other income, net:
Interest income, net	372	179	872	489
Miscellaneous income, net	2,353	2,146	6,660	4,880
Total other income, net	2,725	2,325	7,532	5,369
Income before income taxes	22,030	17,920	61,788	52,331
Income taxes	7,387	6,631	16,778	15,239
Net income	$ 14,643	$ 11,289	$ 45,010	$ 37,092
Net income per share:
Basic	$ 0.56	$ 0.43	$ 1.71	$ 1.4
Diluted	$ 0.54	$ 0.42	$ 1.67	$ 1.36
Shares used in per share computations:
Basic	26,370	26,545	26,362	26,563
Diluted	26,963	27,185	26,976	27,234
Cash dividends declared per common share	$ 0.21	$ 0.18	$ 0.63	$ 0.54