| Document and Entity Information | Oct. 11, 2019 |
| Cover [Abstract] | |
| Entity Registrant Name | NAVIGANT CONSULTING INC |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
| Entity Central Index Key | 0001019737 |
| Document Type | 8-K |
| Document Period End Date | Oct. 11, 2019 |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-12173 |
| Entity Tax Identification Number | 36-4094854 |
| Entity Address, Address Line One | 150 North Riverside Plaza |
| Entity Address, Address Line Two | Suite 2100 |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60606 |
| City Area Code | 312 |
| Local Phone Number | 573-5600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.001 per share |
| Trading Symbol | NCI |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
