Long-Term Incentive Plan (Equity-Based Incentive Compensation Expense) (Details) - Management [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	$ 4,687	$ 4,978	$ 15,226	$ 17,731
G&A Expense [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	4,643	4,862	15,016	17,322
Operating Expenses [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	44	116	210	409
Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	5,277	3,769	14,725	12,128
Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	(590)	1,209	501	5,603
Performance Based Awards [Member] | Two Thousand Twelve Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income		1,673		6,258
Performance Based Awards [Member] | Two Thousand Twelve Awards [Member] | Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income		1,022		3,066
Performance Based Awards [Member] | Two Thousand Twelve Awards [Member] | Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income		651		3,192
Performance Based Awards [Member] | Two Thousand Thirteen Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,083	1,908	6,747	7,137
Performance Based Awards [Member] | Two Thousand Thirteen Awards [Member] | Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,673	1,350	6,246	4,726
Performance Based Awards [Member] | Two Thousand Thirteen Awards [Member] | Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	(590)	558	501	2,411
Performance Based Awards [Member] | Two Thousand Fourteen Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,497	1,101	3,980	3,233
Performance Based Awards [Member] | Two Thousand Fourteen Awards [Member] | Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,497	1,101	3,980	3,233
Performance Based Awards [Member] | Two Thousand Fourteen Awards [Member] | Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	0	0	0	0
Performance Based Awards [Member] | Two Thousand Fifteen Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,727		3,687
Performance Based Awards [Member] | Two Thousand Fifteen Awards [Member] | Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,727		3,687
Performance Based Awards [Member] | Two Thousand Fifteen Awards [Member] | Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	0		0
Retention Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	380	296	812	1,103
Retention Awards [Member] | Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	380	296	812	1,103
Retention Awards [Member] | Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	$ 0	$ 0	$ 0	$ 0