Consolidated Balance Sheets (Parenthetical) - shares	Sep. 30, 2016	Dec. 31, 2015
Equity:
Limited partners' capital account, units outstanding (in shares)	95,339,786	87,365,706
Common Units - Public [Member]
Equity:
Limited partners' capital account, units issued (in shares)	49,588,960	49,588,960
Limited partners' capital account, units outstanding (in shares)	49,588,960	49,588,960
Common Units - Affiliated [Member]
Equity:
Limited partners' capital account, units issued (in shares)	45,750,826	37,776,746
Limited partners' capital account, units outstanding (in shares)	45,750,826	37,776,746
Class A Units - Held by Subsidiary [Member]
Equity:
Limited partners' capital account, units issued (in shares)	0	11,018,744
Limited partners' capital account, units outstanding (in shares)	0	11,018,744
Class C Units - Held by Subsidiary [Member]
Equity:
Limited partners' capital account, units issued (in shares)	16,410,780	0
Limited partners' capital account, units outstanding (in shares)	16,410,780	0