Quarterly Financial Data (Unaudited) - (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue	$ 102,735	$ 100,689	$ 107,117	$ 108,495	$ 107,925	$ 106,418	$ 106,705	$ 103,367	$ 419,036	$ 424,415
Direct costs	80,455	79,506	84,470	85,896	84,478	83,283	83,810	81,515	330,327	333,086	311,984
Gross profit	22,280	21,183	22,647	22,599	23,447	23,135	22,895	21,852	88,709	91,329
Selling, general, and administrative expenses	16,188	15,129	16,248	16,417	17,050	16,812	16,752	16,253	63,982	66,867	64,981
Operating income	6,092	6,054	6,399	6,182	6,397	6,323	6,143	5,599	24,727	24,462	19,310
Interest and other expense, net	(82)	(91)	(106)	(109)	717	(68)	384	(50)	(388)	983
Income before income taxes	6,010	5,963	6,293	6,073	7,114	6,255	6,527	5,549	24,339	25,445	19,123
Provision for income taxes	2,306	2,100	2,238	2,016	2,245	2,442	2,404	2,189	8,660	9,280	7,185
Net Income	3,704	3,863	4,055	4,057	4,869	3,813	4,123	3,360	15,679	16,165	11,938
Basic (in dollars per share)	$ 0.24	$ 0.25	$ 0.26	$ 0.26	$ 0.32	$ 0.25	$ 0.27	$ 0.22	$ 1.02	$ 1.07	$ 0.80
Diluted (in dollars per share)	$ 0.22	$ 0.23	$ 0.24	$ 0.24	$ 0.29	$ 0.23	$ 0.25	$ 0.20	$ 0.92	$ 0.96	$ 0.71
Cash dividend declared per share	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.20	$ 0.00	$ 0.00
Non-taxable life insurance proceeds									0	1,268	0
Interest and Other Income Member [Member]
Basic (in dollars per share)							$ 0.03			$ 0.05
Non-taxable life insurance proceeds					$ 800		$ 400