Employee Incentive Plan (Details Textuals) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended			0 Months Ended		0 Months Ended	9 Months Ended	0 Months Ended
	May 09, 2013 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]		Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	May 09, 2013 CELP Restricted Units [Member] Common Units [Member]	Sep. 30, 2013 CELP Restricted Units [Member] Common Units [Member]	Mar. 04, 2013 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member]	Mar. 04, 2013 Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted units vested and issued				445,177				396,927	[1]				60,018		57,897
Fair value of units vested		$ 1,123,000	$ 448,000	$ 3,307,000	$ 1,714,000	$ 1,275,000	$ 452,000	$ 3,771,000		$ 2,060,000			$ 1,000,000		$ 1,000,000
Unrecognized compensation cost related to non-vested restricted units		$ 9,000,000		$ 9,000,000		$ 9,000,000		$ 9,000,000
Unrecognized compensation cost, period for recognition				1 year 5 months				1 year 6 months
Number of additional shares authorized	1,785,000										3,470,000
Number of shares authorized		4,385,000		4,385,000								9,070,000
Award vesting period														3 years

[1] Vested units include 113,804 units withheld for payroll taxes paid on behalf of employees.