Document and Entity Information
| Document and Entity Information | Nov. 16, 2020 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001574815 |
| Document Type | 8-K |
| Document Period End Date | Nov. 16, 2020 |
| Entity Registrant Name | BMC STOCK HOLDINGS, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-36050 |
| Entity Tax Identification Number | 26-4687975 |
| Entity Address, Address Line One | 4800 Falls of Neuse Road |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Raleigh |
| Entity Address, State or Province | NC |
| Entity Address, Postal Zip Code | 27609 |
| City Area Code | (919) |
| Local Phone Number | 431-1000 |
| Written Communications | true |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, par value $0.01 per share |
| Trading Symbol | BMCH |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |