Fair Value Measurement (Details Textuals) (USD $)							12 Months Ended							9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Other Debt Obligations [Member]	Dec. 31, 2012 Other Debt Obligations [Member] 2016	Dec. 31, 2013 Line of Credit [Member] 2016	Dec. 31, 2012 Line of Credit [Member] 2016	Dec. 31, 2013 Line of Credit [Member] 2016 Four Point Three Percent [Member]	Dec. 31, 2012 Line of Credit [Member] 2016 Four Point Three Percent [Member]	Feb. 02, 2014 Unsecured Debt [Member] 2022	Dec. 31, 2013 Unsecured Debt [Member] 2022 Seven Point One Two Five Percent [Member]	Dec. 31, 2012 Unsecured Debt [Member] 2022 Seven Point One Two Five Percent [Member]	Dec. 31, 2013 CEI Credit Facility [Member]	Dec. 31, 2012 CEI Credit Facility [Member] 2016	Sep. 30, 2013 CEI Credit Facility [Member] 2016 Four Point Three Percent [Member]
Debt Instrument [Line Items]
Borrowed under existing credit facility			$ 12,700,000
Long-term Debt	$ 1,200,472,000	$ 1,036,305,000	$ 13,229,000	$ 0	$ 155,000,000	$ 71,000,000			$ 196,500,000	$ 250,000,000	$ 250,000,000	$ 65,041,000	$ 0
Variable Interest Rate							3.15887%	4.30%						5.30%
Fixed Interest Rate										7.125%