BUSINESS COMBINATION (Details) $ / shares in Units, $ in Millions					3 Months Ended	12 Months Ended		24 Months Ended
	Jun. 01, 2018 shares	Jan. 14, 2018 shares	Sep. 19, 2017 shares	Feb. 27, 2017 USD ($) item $ / shares shares	Jun. 30, 2018 shares	Dec. 31, 2018 shares	Dec. 31, 2017 USD ($)	Dec. 31, 2019 shares
Common stock shares outstanding						64,455,174		64,589,075
Number of shares issued								0
Common stock shares sold (in shares)						64,455,174		64,589,075
Issuance of common stock (in shares)		7,500,000	5,292,000			5,675,967
Term loan facility
Credit facility | $				$ 250.0
Delayed Draw Feature
Credit facility | $				100.0
ABL Member
Credit facility | $				$ 70.0
Minimum
Earn out target ( as a percent)				90.00%
Maximum
Earn out target ( as a percent)				100.00%
IPO
Issuance of common stock (in shares)			4,882,167
Private placement
Common stock shares sold (in shares)				419,669
Series A
Proceeds from convertible preferred stock | $							$ 65.0
Senior Debt
Credit facility | $				$ 350.0
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc
Common stock shares outstanding				37,715,960
Common stock shares sold (in shares)				37,715,960
Proceeds from convertible preferred stock | $				$ 65.0
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | IPO
Common stock shares sold (in shares)				8,342,918
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Private placement
Common stock shares sold (in shares)				2,288,043
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Private placement | Maximum
Value per share issued | $ / shares				$ 10.00
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Series A
Proceeds from convertible preferred stock | $				$ 65.0
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Series A | Private placement
Proceeds from convertible preferred stock | $				$ 65.0
Issuance of common stock (in shares)				650,000
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Earn out provision
Number of trading days | item				20
Number of consecutive trading days				30 days
Number of shares issued	5,000,000
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Earn out provision | Minimum
Adjusted EBITDA - 2017 | $				$ 140.0
Adjusted EBITDA - 2018 | $				170.0
Adjusted EBITDA - 2019 | $				$ 200.0
Share price - 2017 | $ / shares				$ 12.00
Share price - 2018 | $ / shares				14.00
Share price - 2019 | $ / shares				$ 16.00
Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Earn out provision | Maximum
Shares payable annually in 2018				5,000,000
Shares payable annually in 2019				5,000,000
Private Daseke
Number of shares issued				26,665,330	5,000,000
Private Daseke | Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc
Consideration received upon closing | $				$ 266.7
Private Daseke | Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Maximum
Value per share issued | $ / shares				$ 10.00
Private Daseke | Hennessy Capital Acquisition Corp II and HCAC Merger Sub Inc | Earn out provision | Maximum
Shares to be issued under earn-out provision				15,000,000
Shares payable annually in 2017				5,000,000