Equity compensation plans (Tables)

6 Months Ended

Jun. 30, 2018

Equity compensation plans

Schedule of changes in outstanding LTIP notional units

		Grant Date
		Weighted-Average
	Units	Fair Value per Unit
Outstanding at December 31, 2017	2,884,574		2.22
Granted	2,483,237		2.02
Vested and redeemed	(1,216,252)		2.24
Outstanding at June 30, 2018	4,151,559	$	2.09