Consolidated Statement of Changes in Capital (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year (in shares)	25,023,128
Balance at beginning of year	$ 476,419	$ 492,508
Net income (loss)	(61,607)	15,622
Currency translation adjustments	(2,936)	1,303
Equity compensation - restricted units	104	164
Deconsolidation of API (see Note 3)	17,481
Other, net	$ 58
Unrealized gains on derivative financial instruments		518
Purchases of SPLP common units		(6,721)
Balance at end of period (in shares)	25,013,274
Balance at end of year	$ 429,519	503,394
Total Partners' Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	472,613	488,787
Net income (loss)	(61,737)	15,678
Currency translation adjustments	(2,936)	1,303
Equity compensation - restricted units	104	164
Deconsolidation of API (see Note 3)	17,481
Other, net	(2)
Unrealized gains on derivative financial instruments		518
Purchases of SPLP common units		(6,721)
Balance at end of year	$ 425,523	$ 499,729
Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year (in shares)	37,670,992	37,436,531
Equity compensation - restricted units (in shares)	(9,854)	170,000
Balance at end of period (in shares)	37,661,138	37,606,531
Treasury Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year (in shares)	12,647,864	12,142,528
Balance at beginning of year	$ (198,781)	$ (192,060)
Purchases of SPLP common units (in shares)		(505,336)
Purchases of SPLP common units		$ (6,721)
Balance at end of period (in shares)	12,647,864	12,647,864
Balance at end of year	$ (198,781)	$ (198,781)
Partners' Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	664,035	666,031
Net income (loss)	(61,737)	15,678
Equity compensation - restricted units	104	164
Other, net	(2)
Purchases of SPLP common units		(6,721)
Balance at end of year	602,400	675,152
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	(191,422)	(177,244)
Currency translation adjustments	(2,936)	1,303
Deconsolidation of API (see Note 3)	17,481
Unrealized gains on derivative financial instruments		518
Balance at end of year	(176,877)	(175,423)
Noncontrolling Interests in Consolidated Entities
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	3,806	3,721
Net income (loss)	130	(56)
Other, net	60
Balance at end of year	$ 3,996	$ 3,665