Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Trade accounts receivable, allowance for doubtful accounts	$ 0	$ 0
Other intangibles, accumulated amortization	13,029	11,526
Debt placement costs, accumulated amortization	$ 10,819	$ 8,952
Limited partner unitholders, units outstanding	227,427,247	227,068,257