Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018
Revenues:
Revenues before reimbursements	$ 95,506	$ 88,714	$ 289,170	$ 269,370
Reimbursements	6,042	6,588	17,915	18,010
Revenues	101,548	95,302	307,085	287,380
Operating expenses:
Compensation and related expenses	58,526	55,639	185,616	168,676
Other operating expenses	8,345	7,826	24,448	22,857
Reimbursable expenses	6,042	6,588	17,915	18,010
General and administrative expenses	5,451	4,655	15,345	13,167
Total operating expenses	78,364	74,708	243,324	222,710
Operating income	23,184	20,594	63,761	64,670
Other income, net:
Interest income, net	915	740	2,894	1,813
Miscellaneous income, net	1,112	2,655	10,729	4,875
Total other income, net	2,027	3,395	13,623	6,688
Income before income taxes	25,211	23,989	77,384	71,358
Income taxes	5,578	6,536	14,045	15,140
Net income	$ 19,633	$ 17,453	$ 63,339	$ 56,218
Net income per share:
Basic (in dollars per share)	$ 0.37	$ 0.33	$ 1.20	$ 1.06
Diluted (in dollars per share)	$ 0.36	$ 0.32	$ 1.17	$ 1.04
Shares used in per share computations:
Basic (in shares)	52,802	53,032	52,694	52,928
Diluted (in shares)	54,002	54,302	53,906	54,181
Cash dividends declared per common share (in dollars per share)	$ 0.160	$ 0.130	$ 0.480	$ 0.390