Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenues before reimbursements		$ 196,567	$ 165,224	$ 382,696	$ 326,669
Reimbursements		26,489	19,489	43,222	36,112
Total revenues		223,056	184,713	425,918	362,781
Cost of services before reimbursable expenses		140,405	113,121	275,761	230,057
Reimbursable expenses		26,489	19,489	43,222	36,112
Total cost of services		166,894	132,610	318,983	266,169
General and administrative expenses		35,968	34,912	71,135	71,991
Depreciation expense		4,262	4,943	8,848	9,940
Amortization expense		1,393	1,665	2,765	3,417
Other operating costs			2,295	32	3,278
Operating income		14,539	8,288	24,155	7,986
Interest expense		317	911	635	1,739
Interest income		(375)	(77)	(1,064)	(196)
Other (income) expense, net		(10)	(183)	122	178
Income from continuing operations before income tax expense		14,607	7,637	24,462	6,265
Income tax expense		3,682	1,509	6,729	1,734
Net income from continuing operations		10,925	6,128	17,733	4,531
Income from discontinued operations, net of tax		523	22,698	34	36,148
Net income		11,448	28,826	17,767	40,679
Less: Income attributable to non-controlling interest, net of tax		(2,369)		(4,407)
Net income attributable to Navigant Consulting, Inc.		$ 9,079	$ 28,826	$ 13,360	$ 40,679
Basic net income per share
Net income from continuing operations attributable to Navigant Consulting, Inc.		$ 0.22	$ 0.14	$ 0.34	$ 0.10
Income from discontinued operations, net of tax		0.01	0.50		0.80
Net income attributable to Navigant Consulting, Inc.	[1]	$ 0.23	$ 0.64	$ 0.34	$ 0.90
Shares used in computing basic per share data		38,654	45,106	39,436	45,113
Diluted net income per share
Net income from continuing operations attributable to Navigant Consulting, Inc.		$ 0.22	$ 0.13	$ 0.33	$ 0.10
Income from discontinued operations, net of tax		0.01	0.49		0.77
Net income attributable to Navigant Consulting, Inc.	[1]	$ 0.23	$ 0.62	$ 0.33	$ 0.87
Shares used in computing diluted per share data		39,616	46,549	40,512	46,692
Net income		$ 11,448	$ 28,826	$ 17,767	$ 40,679
Other comprehensive income (loss), net of tax:
Unrealized net gain (loss), foreign currency translation		(1,042)	3,406	(600)	2,037
Unrealized net gain on interest rate derivatives			112		362
Reclassification adjustment on interest rate derivatives included in interest expense and income tax expense			(39)		(32)
Other comprehensive income (loss), net of tax		1,042	(3,333)	600	(1,707)
Total comprehensive income, net of tax		12,490	25,493	18,367	38,972
Income attributable to non-controlling interest, net of tax		(2,369)		(4,407)
Total comprehensive income attributable to Navigant Consulting, Inc., net of tax		$ 10,121	$ 25,493	$ 13,960	$ 38,972

[1] Earnings per share may not foot due to rounding.