Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Total	General Partner [Member]	Common Unitholders [Member]	Accumulated Other Comprehensive Income [Member]	Common Unitholders, Units [Member]
Partners' capital rollforward
Common units issued and outstanding			33,142,000
Net Income (Loss) Allocated to General Partners	$ (1,892)
Beginning balance at Dec. 31, 2014	550,281	$ 11,341	$ 542,276	$ (3,336)
Partners' capital rollforward
Net income	(146,630)	(1,892)	(144,738)	0
Distributions	(68,360)	(2,607)	(65,753)	0
Equity compensation	1,924	0	1,924	0
Vesting of Phantom Units	0	0	$ 0	0
Vesting of Phantom Units, number of units			44,000
Other comprehensive income (loss)	(5,057)	0	$ 0	(5,057)
Ending balance at Dec. 31, 2015	332,158	6,842	$ 333,709	(8,393)
Partners' capital rollforward
Net Income (Loss) Allocated to Limited Partners	(144,738)
Common units issued and outstanding			33,186,000
Net Income (Loss) Allocated to General Partners	(2,763)
Net income	(138,138)	(2,763)	$ (135,375)	0
Distributions	(51,254)	(1,018)	(50,236)	0
Equity compensation	2,541	0	2,541	0
Vesting of Phantom Units	0	0	0	0
Temporary Equity, Other Changes	(40)		$ (40)
Vesting of Phantom Units, number of units			76,000
Other comprehensive income (loss)	(2,018)	0	$ 0	(2,018)
Ending balance at Dec. 31, 2016	143,249	3,061	$ 150,599	(10,411)
Partners' capital rollforward
Net Income (Loss) Allocated to Limited Partners	$ (135,375)
Common units issued and outstanding	33,262,376		33,262,000
Net Income (Loss) Allocated to General Partners		(809)
Net income	$ (40,459)			0
Distributions	(33,068)	(634)	$ (32,434)	0
Equity compensation	862	0	862	0
Vesting of Phantom Units	$ 0	0	0	0
Conversion of Stock, Shares Converted	3,705,000
Conversion of Stock, Amount Converted	$ 22,848			0	$ 22,848
Charges settled with common units, units issued	439,000
charges settled with common units, amount	$ 3,322			0	$ 3,322
Partners' Capital, Other	(1,078)	0	$ 0	(1,078)
Vesting of Phantom Units, number of units			212,000
Other comprehensive income (loss)	(649)	0	$ (649)	0
Ending balance at Dec. 31, 2017	$ 95,027	$ 1,618	104,898	$ (11,489)
Partners' capital rollforward
Net Income (Loss) Allocated to Limited Partners			$ (39,650)
Common units issued and outstanding	37,618,734		37,618,000