CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	CRA International, Inc. Shareholders' Equity	Common Stock	Receivables from Shareholders	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interest	Total
BALANCE at Dec. 29, 2012	$ 211,276	$ 93,174	$ (120)	$ 122,610	$ (4,388)	$ 958	$ 212,234
BALANCE (in shares) at Dec. 29, 2012		10,057,448
Increase (Decrease) in Shareholders' Equity
Net income (loss)	11,370			11,370		(135)	11,235
Foreign currency translation adjustment	964				964		964
Exercise of stock options	207	$ 207					$ 207
Exercise of stock options (in shares)		13,389					13,389
Share-based compensation expense for employees	2,888	$ 2,888					$ 2,888
Share-based compensation expense for non-employees	147	$ 147					147
Restricted share vesting (in shares)		134,384
Redemption of vested employee restricted shares for tax withholding	(730)	$ (730)					(730)
Redemption of vested employee restricted shares for tax withholding (in shares)		(37,642)
Tax benefit on stock option exercises and restricted shares vesting	(254)	$ (254)					(254)
Payments received on notes receivable from shareholders	120		$ 120				120
Shares repurchased	(2,190)	$ (2,190)					$ (2,190)
Shares repurchased (in shares)		(118,968)					(118,968)
Equity transactions of noncontrolling interest						16	$ 16
BALANCE at Dec. 28, 2013	223,798	$ 93,242		133,980	(3,424)	839	224,637
BALANCE (in shares) at Dec. 28, 2013		10,048,611
Increase (Decrease) in Shareholders' Equity
Net income (loss)	13,638			13,638		(231)	13,407
Foreign currency translation adjustment	(3,280)				(3,280)		(3,280)
Issuance of common stock in connection with business acquisition	427	$ 427					427
Issuance of common stock in connection with business acquisition (in shares)		22,520
Exercise of stock options	469	$ 469					$ 469
Exercise of stock options (in shares)		20,931					20,931
Share-based compensation expense for employees	5,348	$ 5,348					$ 5,348
Share-based compensation expense for non-employees	271	$ 271					271
Restricted share vesting (in shares)		149,195
Redemption of vested employee restricted shares for tax withholding	(1,222)	$ (1,222)					(1,222)
Redemption of vested employee restricted shares for tax withholding (in shares)		(41,470)
Tax benefit on stock option exercises and restricted shares vesting	128	$ 128					128
Shares repurchased	(25,492)	$ (25,492)					$ (25,492)
Shares repurchased (in shares)		(971,515)					(971,515)
Equity transactions of noncontrolling interest						11	$ 11
BALANCE at Jan. 03, 2015	214,085	$ 73,171		147,618	(6,704)	619	$ 214,704
BALANCE (in shares) at Jan. 03, 2015		9,228,272					9,228,272
Increase (Decrease) in Shareholders' Equity
Net income (loss)	7,657			7,657		(1,332)	$ 6,325
Foreign currency translation adjustment	(2,546)				(2,546)		(2,546)
Issuance of common stock in connection with business acquisition	42	$ 42					42
Issuance of common stock in connection with business acquisition (in shares)		1,359
Exercise of stock options	602	$ 602					$ 602
Exercise of stock options (in shares)		29,288					29,288
Share-based compensation expense for employees	5,755	$ 5,755					$ 5,755
Share-based compensation expense for non-employees	11	$ 11					11
Restricted share vesting (in shares)		106,504
Redemption of vested employee restricted shares for tax withholding	(668)	$ (668)					(668)
Redemption of vested employee restricted shares for tax withholding (in shares)		(28,900)
Tax benefit on stock option exercises and restricted shares vesting	(376)	$ (376)					(376)
Shares repurchased	(12,806)	$ (12,806)					$ (12,806)
Shares repurchased (in shares)		(477,292)					(477,292)
Equity transactions of noncontrolling interest						25	$ 25
BALANCE at Jan. 02, 2016	$ 211,756	$ 65,731		$ 155,275	$ (9,250)	$ (688)	$ 211,068
BALANCE (in shares) at Jan. 02, 2016		8,859,231					8,859,231