Revenue Recognition (Impact on Balance Sheet and Operating Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
ASSETS
Accounts receivable - trade, net	$ 432,777		$ 432,777		$ 447,421	$ 495,449
Inventories	92,520		92,520		93,791	88,653
Other assets, net of amortization	118,170		118,170		115,832	56,628
LIABILITIES AND CAPITAL
Other long-term liabilities	293,524		293,524		276,435	256,571
Partners' capital	1,881,957		1,881,957		2,022,597	$ 2,026,147
OPERATING INCOME
Total revenues	752,388		1,478,196
Operating Income	60,900	$ 61,447	119,981	$ 114,044
Offshore Pipeline Transportation
OPERATING INCOME
Total revenues	69,969		143,229
Cost of revenues	17,440		35,780
Sodium Minerals & Sulfur Services
OPERATING INCOME
Total revenues	298,881		584,791
Cost of revenues	232,517		456,015
Marine Transportation
OPERATING INCOME
Total revenues	56,185		105,114
Cost of revenues	44,217		82,064
Onshore facilities and transportation
OPERATING INCOME
Total revenues	327,353		645,062
Onshore facilities and transportation | Onshore facilities and transportation product costs
OPERATING INCOME
Cost of revenues	283,059		560,877
Onshore facilities and transportation | Onshore facilities and transportation operating costs
OPERATING INCOME
Cost of revenues	23,046		45,341
Effect of Change Increase/(Decrease)
OPERATING INCOME
Total revenues	30,877		51,971
Operating Income	2,179		(772)
Effect of Change Increase/(Decrease) | Offshore Pipeline Transportation
OPERATING INCOME
Total revenues	1,147		296
Cost of revenues	0		0
Effect of Change Increase/(Decrease) | Sodium Minerals & Sulfur Services
OPERATING INCOME
Total revenues	29,730		51,675
Cost of revenues	28,699		52,743
Effect of Change Increase/(Decrease) | Marine Transportation
OPERATING INCOME
Total revenues	0		0
Cost of revenues	0		0
Effect of Change Increase/(Decrease) | Onshore facilities and transportation
OPERATING INCOME
Total revenues	0		0
Effect of Change Increase/(Decrease) | Onshore facilities and transportation | Onshore facilities and transportation product costs
OPERATING INCOME
Cost of revenues	0		0
Effect of Change Increase/(Decrease) | Onshore facilities and transportation | Onshore facilities and transportation operating costs
OPERATING INCOME
Cost of revenues	0		0
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606
ASSETS
Accounts receivable - trade, net	484,990		484,990
Inventories	88,451		88,451
Other assets, net of amortization	51,098		51,098
LIABILITIES AND CAPITAL
Other long-term liabilities	270,274		270,274
Partners' capital	1,886,279		1,886,279
OPERATING INCOME
Total revenues	721,511		1,426,225
Operating Income	58,721		120,753
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606 | Offshore Pipeline Transportation
OPERATING INCOME
Total revenues	68,822		142,933
Cost of revenues	17,440		35,780
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606 | Sodium Minerals & Sulfur Services
OPERATING INCOME
Total revenues	269,151		533,116
Cost of revenues	203,818		403,272
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606 | Marine Transportation
OPERATING INCOME
Total revenues	56,185		105,114
Cost of revenues	44,217		82,064
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606 | Onshore facilities and transportation
OPERATING INCOME
Total revenues	327,353		645,062
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606 | Onshore facilities and transportation | Onshore facilities and transportation product costs
OPERATING INCOME
Cost of revenues	283,059		560,877
Accounting Standards Update 2014-09 | Adjustment/Without adoption of ASC 606 | Onshore facilities and transportation | Onshore facilities and transportation operating costs
OPERATING INCOME
Cost of revenues	23,046		45,341
Accounting Standards Update 2014-09 | Effect of Change Increase/(Decrease)
ASSETS
Accounts receivable - trade, net	(52,213)		(52,213)		(48,028)
Inventories	4,069		4,069		5,138
Other assets, net of amortization	67,072		67,072		59,204
LIABILITIES AND CAPITAL
Other long-term liabilities	23,250		23,250		19,864
Partners' capital	$ (4,322)		$ (4,322)		$ (3,550)