Distributions and Net Income Per Limited Partner Unit (Basic and Diluted Income Per Limited Partner Unit) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 9,834	$ 8,575
(Distribution in excess of net income) net income in excess of distribution	(70)	3,509
Net income	$ 9,764	$ 12,084
Weighted average units outsanding:
Basic and diluted (shares)	27,059,730	27,059,730
Common units [Member]
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 5,101	$ 4,554
(Distribution in excess of net income) net income in excess of distribution	(37)	1,864
Net income	$ 5,064	$ 6,418
Weighted average units outsanding:
Basic and diluted (shares)	14,373,615	14,373,615
Net income per limited partner unit:
Income per limited partner unit (usd per share)	$ 0.35	$ 0.45
Subordinated units [Member]
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 4,502	$ 4,019
(Distribution in excess of net income) net income in excess of distribution	(33)	1,645
Net income	$ 4,469	$ 5,664
Weighted average units outsanding:
Basic and diluted (shares)	12,686,115	12,686,115
Net income per limited partner unit:
Income per limited partner unit (usd per share)	$ 0.35	$ 0.45
IDR Holders [Member]
Limited Partners' Capital Account [Line Items]
Subsequent distribution to IDR holders	$ 231	$ 2
(Distribution in excess of net income) net income in excess of distribution	0	0
Net income	$ 231	$ 2