(LOSS) INCOME PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net (loss) income attributable to Diplomat Pharmacy, Inc.	$ (298,025)	$ 169	$ (3,964)	$ (450)	$ 6,536	$ 1,016	$ 3,591	$ 4,367	$ (302,269)	$ 15,510	$ 28,273
Denominator:
Weighted average common shares outstanding, basic (in shares)									74,244,520	68,130,322	65,970,396
Weighted average dilutive effect of stock options, RSAs and RSUs									399,522	649,731	1,739,750
Weighted average dilutive effect of contingent consideration (in shares)											337,577
Weighted average common shares outstanding, diluted (in shares)									74,244,520	68,780,053	68,047,723
Net (loss) income per common share:
Basic (in dollars per share)	$ (4.00)	$ 0.00	$ (0.05)	$ (0.01)	$ 0.09	$ 0.01	$ 0.05	$ 0.07	$ (4.07)	$ 0.23	$ 0.43
Diluted (in dollars per share)	$ (4.00)	$ 0.00	$ (0.05)	$ (0.01)	$ 0.09	$ 0.01	$ 0.05	$ 0.06	$ (4.07)	$ 0.23	$ 0.42