Net Income Per Share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Net income available to common shareholders
Net income attributable to CRA as reported	$ 6,468	$ 4,665
Less: net income attributable to participating shares	26	16
Net income available to common shareholders	$ 6,442	$ 4,649
Reconciliation of basic to diluted weighted average shares of common stock outstanding
Basic weighted average shares outstanding	7,805,000	8,015,000
Dilutive stock options and restricted stock units	232,000	331,000
Diluted weighted average shares outstanding	8,037,000	8,346,000
Calculation of common stock equivalents for purposes of computing diluted weighted average shares outstanding
Anti-dilutive securities excluded from EPS computation (in shares)	73,647	20,078