Supplemental Guarantor / Non-Guarantor Financial Information Condensed Consolidating Statement of Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended
	Feb. 05, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Revenues		$ 127,731			$ 135,895			$ 370,392	$ 401,143
Operating costs and expenses [Abstract]
Operations (exclusive of depreciation and amortization)		40,003			44,924			109,721	123,045
Depreciation and amortization		26,190			24,121			75,202	72,192
Goodwill, Impairment Loss		35,653			0			35,653	0
General and administrative		2,332			2,714			7,569	7,322
Total operating costs and expenses		104,178			71,759			228,145	202,559
Operating Income (Loss)		23,553			64,136			142,247	198,584
Equity in earnings of subsidiaries		0			0				0
Equity in earnings of equity method investments		1,316			1,334			5,186	5,217
Interest expense		(14,104)			(18,807)			(45,650)	(57,059)
Interest income		2,803			2,243			7,834	3,322
Gain (Loss) on Extinguishment of Debt	$ 25,900	0			0			(25,915)	0
Other Nonoperating Income (Expense)								8,439
Gain on Sales-type Leases		0			35,166			33,834	35,166
Gain on sale of assets and other		7,465			142			8,439	(57)
Nonoperating Income (Expense)		(2,520)			20,078			(16,272)	(13,411)
Income before income taxes		21,033			84,214			125,975	185,173
State income tax benefit (expense)		(34)			(30)			(110)	(36)
Net income		20,999	$ 77,954	$ 26,912	84,184	$ 47,159	$ 53,794	125,865	185,137
Allocation of net income attributable to noncontrolling interests		(3,186)			(1,839)			(6,721)	(5,920)
Net Income (Loss) Attributable to Parent		17,813			82,345			119,144	179,217
Other Comprehensive Income (Loss), Net of Tax								0
Net income attributable to the partners		17,813			82,345			119,144	179,217
Parent
Revenues:
Revenues		0			0			0	0
Operating costs and expenses [Abstract]
Operations (exclusive of depreciation and amortization)		0			0			0	0
Depreciation and amortization		0						0
Goodwill, Impairment Loss		0						0
General and administrative		649			569			2,528	2,390
Total operating costs and expenses		649			569			2,528	2,390
Operating Income (Loss)		(649)			(569)			(2,528)	(2,390)
Equity in earnings of subsidiaries		31,461			101,638				238,368
Equity in earnings of equity method investments		0			0			0	0
Interest expense		(13,072)			(18,945)			(42,542)	(56,982)
Interest income		0			0			26	0
Gain (Loss) on Extinguishment of Debt								(25,915)
Other Nonoperating Income (Expense)								214
Gain on Sales-type Leases					0			0	0
Gain on sale of assets and other		73			221				221
Nonoperating Income (Expense)		18,462			82,914			121,672	181,607
Income before income taxes		17,813			82,345			119,144	179,217
State income tax benefit (expense)		0			0			0	0
Net income		17,813			82,345			119,144	179,217
Allocation of net income attributable to noncontrolling interests		0			0			0	0
Other Comprehensive Income (Loss), Net of Tax								189,889
Net income attributable to the partners		17,813			82,345			119,144	179,217
Guarantor Restricted Subsidiaries
Revenues:
Revenues		116,145			123,481			335,359	362,860
Operating costs and expenses [Abstract]
Operations (exclusive of depreciation and amortization)		36,065			40,866			98,176	111,644
Depreciation and amortization		21,997			19,757			62,489	59,320
Goodwill, Impairment Loss		35,653						35,653
General and administrative		1,683			2,145			5,041	4,932
Total operating costs and expenses		95,398			62,768			201,359	175,896
Operating Income (Loss)		20,747			60,713			134,000	186,964
Equity in earnings of subsidiaries		6,589			3,013				10,572
Equity in earnings of equity method investments		755			1,334			4,292	5,217
Interest expense		(1,032)			138			(3,108)	(77)
Interest income		2,787			2,243			7,792	3,322
Gain (Loss) on Extinguishment of Debt								0
Other Nonoperating Income (Expense)								3,358
Gain on Sales-type Leases					35,166			33,834	35,166
Gain on sale of assets and other		2,542			(104)				(364)
Nonoperating Income (Expense)		11,641			41,790			58,562	53,836
Income before income taxes		32,388			102,503			192,562	240,800
State income tax benefit (expense)		(34)			(30)			(110)	(36)
Net income		32,354			102,473			192,452	240,764
Allocation of net income attributable to noncontrolling interests		(893)			(835)			(2,563)	(2,396)
Other Comprehensive Income (Loss), Net of Tax								12,394
Net income attributable to the partners		31,461			101,638			189,889	238,368
Non-Guarantor Non-Restricted Subsidiaries
Revenues:
Revenues		11,586			12,414			35,033	38,283
Operating costs and expenses [Abstract]
Operations (exclusive of depreciation and amortization)		3,938			4,058			11,545	11,401
Depreciation and amortization		4,193			4,364			12,713	12,872
Goodwill, Impairment Loss		0						0
General and administrative		0			0			0	0
Total operating costs and expenses		8,131			8,422			24,258	24,273
Operating Income (Loss)		3,455			3,992			10,775	14,010
Equity in earnings of subsidiaries		0			0				0
Equity in earnings of equity method investments		561			0			894	0
Interest expense		0			0			0	0
Interest income		16			0			16	0
Gain (Loss) on Extinguishment of Debt								0
Other Nonoperating Income (Expense)								4,867
Gain on Sales-type Leases					0			0	0
Gain on sale of assets and other		4,850			25				86
Nonoperating Income (Expense)		5,427			25			5,777	86
Income before income taxes		8,882			4,017			16,552	14,096
State income tax benefit (expense)		0			0			0	0
Net income		8,882			4,017			16,552	14,096
Allocation of net income attributable to noncontrolling interests		(2,293)			(1,004)			(4,158)	(3,524)
Other Comprehensive Income (Loss), Net of Tax								0
Net income attributable to the partners		6,589			3,013			12,394	10,572
Eliminations
Revenues:
Revenues		0			0			0	0
Operating costs and expenses [Abstract]
Operations (exclusive of depreciation and amortization)		0			0			0	0
Depreciation and amortization		0			0			0	0
Goodwill, Impairment Loss		0						0
General and administrative		0			0			0	0
Total operating costs and expenses		0			0			0	0
Operating Income (Loss)		0			0			0	0
Equity in earnings of subsidiaries		(38,050)			(104,651)				(248,940)
Equity in earnings of equity method investments		0			0			0	0
Interest expense		0			0			0	0
Interest income		0			0			0	0
Gain (Loss) on Extinguishment of Debt								0
Other Nonoperating Income (Expense)								0
Gain on Sales-type Leases					0			0	0
Gain on sale of assets and other		0			0				0
Nonoperating Income (Expense)		(38,050)			(104,651)			(202,283)	(248,940)
Income before income taxes		(38,050)			(104,651)			(202,283)	(248,940)
State income tax benefit (expense)		0			0			0	0
Net income		(38,050)			(104,651)			(202,283)	(248,940)
Allocation of net income attributable to noncontrolling interests		0			0			0	0
Other Comprehensive Income (Loss), Net of Tax								(202,283)
Net income attributable to the partners		(38,050)			(104,651)			(202,283)	(248,940)
Affiliates
Revenues:
Revenues		100,992			106,027			297,983	311,755
Affiliates | Parent
Revenues:
Revenues		0			0			0	0
Affiliates | Guarantor Restricted Subsidiaries
Revenues:
Revenues		94,595			99,482			278,767	293,096
Affiliates | Non-Guarantor Non-Restricted Subsidiaries
Revenues:
Revenues		6,397			6,545			19,216	18,659
Affiliates | Eliminations
Revenues:
Revenues		0			0			0	0
Third parties
Revenues:
Revenues		26,739			29,868			72,409	89,388
Third parties | Parent
Revenues:
Revenues		0			0			0	0
Third parties | Guarantor Restricted Subsidiaries
Revenues:
Revenues		21,550			23,999			56,592	69,764
Third parties | Non-Guarantor Non-Restricted Subsidiaries
Revenues:
Revenues		5,189			5,869			15,817	19,624
Third parties | Eliminations
Revenues:
Revenues		$ 0			$ 0			$ 0	$ 0