Consolidated Statement of Changes in Capital $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) shares
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	$ 704,258
Balance at beginning of year (in shares) | shares	26,152,976
Net loss	$ (3,098)
Unrealized gains on available-for-sale securities	17,831
Unrealized gains derivative financial instruments	307
Currency translation adjustments	1,227
Equity compensation - incentive units and vesting of restricted units	5,282
Equity compensation - subsidiaries	675
Purchases of SPLP common units	(1,306)
Purchases of subsidiary shares from noncontrolling interests	(65,589)
Other, net	(62)
Balance at end of year	$ 659,525
Balance at end of period (in shares) | shares	26,083,971
Total Partners' Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	$ 548,741
Net loss	(4,082)
Unrealized gains on available-for-sale securities	17,020
Unrealized gains derivative financial instruments	280
Currency translation adjustments	987
Equity compensation - incentive units and vesting of restricted units	5,282
Equity compensation - subsidiaries	425
Purchases of SPLP common units	(1,306)
Purchases of subsidiary shares from noncontrolling interests	21,497
Other, net	112
Balance at end of year	$ 588,956
Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year (in shares) | shares	36,711,663
Equity compensation - restricted units (shares) | shares	0
Balance at end of period (in shares) | shares	36,711,663
Treasury Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	$ (164,900)
Balance at beginning of year (in shares) | shares	10,558,687
Purchases of SPLP common units	$ (1,306)
Purchases of SPLP common units (shares) | shares	(69,005)
Balance at end of year	$ (166,206)
Balance at end of period (in shares) | shares	10,627,692.000
Partners' Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	$ 617,502
Net loss	(4,082)
Equity compensation - incentive units and vesting of restricted units	5,282
Equity compensation - subsidiaries	425
Purchases of SPLP common units	(1,306)
Purchases of subsidiary shares from noncontrolling interests	20,649
Other, net	112
Balance at end of year	638,582
Accumulated Other Comprehensive Income
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	(68,761)
Unrealized gains on available-for-sale securities	17,020
Unrealized gains derivative financial instruments	280
Currency translation adjustments	987
Purchases of subsidiary shares from noncontrolling interests	848
Balance at end of year	(49,626)
Non-controlling interests in Consolidated Entities
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at beginning of year	155,517
Net loss	984
Unrealized gains on available-for-sale securities	811
Unrealized gains derivative financial instruments	27
Currency translation adjustments	240
Equity compensation - subsidiaries	250
Purchases of subsidiary shares from noncontrolling interests	(87,086)
Other, net	(174)
Balance at end of year	$ 70,569