Long-Term Incentive Plan (Equity-Based Incentive Compensation Expense) (Details) - Management [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	$ 6,650	$ 4,751
G&A Expense [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	6,608	4,689
Operating Expenses [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	42	62
Equity Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	6,650	4,536
Liability Method [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	0	215
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		1,734
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		1,519
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		215
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	3,409	1,623
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	3,409	1,623
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
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	1,545	1,019
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	1,545	1,019
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
Performance Based Awards [Member] | Two Thousand Sixteen Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	1,120
Performance Based Awards [Member] | Two Thousand Sixteen 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	1,120
Performance Based Awards [Member] | Two Thousand Sixteen 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
Retention Awards [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Allocation of LTIP expense on consolidated statements of income	576	375
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	576	375
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