CONSOLIDATED AND CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Revenues:
Terminalling and storage	[1]	$ 24,064	$ 24,658
Marine transportation	[1]	11,454	12,821
Natural gas services	[1]	15,356	14,665
Sulfur services		2,787	2,850
Product sales:
Natural gas services	[1]	159,163	126,657
Sulfur services	[1]	34,900	39,527
Terminalling and storage	[1]	36,480	32,147
Total product sales	[1]	230,543	198,331
Total revenues		284,204	253,325
Cost of products sold: (excluding depreciation and amortization)
Natural gas services	[1]	142,957	108,179
Sulfur services	[1]	23,896	24,483
Terminalling and storage	[1]	31,413	26,446
Total cost of products sold (excluding depreciation and amortization)	[1]	198,266	159,108
Expenses:
Operating expenses	[1]	33,001	35,057
Selling, general and administrative	[1]	9,668	9,921
Depreciation and amortization		19,210	25,336
Total costs and expenses		260,145	229,422
Other operating loss		(2)	(155)
Operating income		24,057	23,748
Other income (expense):
Equity in earnings of WTLPG		1,595	905
Interest expense, net		(12,685)	(10,920)
Other, net		0	30
Total other expense		(11,090)	(9,985)
Net income before taxes		12,967	13,763
Income tax expense		(149)	(180)
Net income		12,818	13,583
Less general partner's interest in net income		(256)	(272)
Less income allocable to unvested restricted units		(8)	(35)
Limited partners' interest in net income		$ 12,554	$ 13,276
Net income per unit attributable to limited partners - basic (USD per share)		$ 0.33	$ 0.36
Net income per unit attributable to limited partners - diluted (USD per share)		$ 0.32	$ 0.36
Weighted average limited partner units - basic (in shares)		38,621,375	37,321,263
Weighted average limited partner units - diluted (in shares)		38,629,627	37,367,384

[1] Related Party Transactions Included Above     Three Months Ended     March 31,     2018   2017 Revenues:*         Terminalling and storage   $ 20,025
  $ 19,704
Marine transportation   3,613
  4,325
Natural gas services   —
  112
Product Sales   642
  1,430
Costs and expenses:*         Cost of products sold: (excluding depreciation and amortization)         Natural gas services   4,318
  8,894
Sulfur services   4,526
  3,675
Terminalling and storage   6,558
  5,067
Expenses:         Operating expenses   13,384
  16,376
Selling, general and administrative   7,721
  7,568