Borrowings Under Credit Facilities and Related Items (Details Textual)	6 Months Ended
	Jun. 30, 2015 USD ($) Number		Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)
Line Of Credit Facility [Line Items]
Unsecured line of credit arrangement	$ 2,500,000,000
Additional unsecured line of credit arrangement	1,000,000,000
Maximum aggregate commitment	$ 3,500,000,000
Number of banks in consortium | Number	28
Available to borrow in alternate currencies	$ 500,000,000
Agent bank's prime rate of interest	1.112%
Interest Rate margin	0.925%
Annual facility fee for each bank based on commitment amount	0.15%
Debt instrument maturity date	Oct. 31, 2018
Balance outstanding at quarter end	$ 350,000,000	[1]	$ 0	$ 0
Term Loan Interest Rate Margin	1.15%
HCN Term Loan	$ 500,000,000
HCN Canadian Denomiated Term Loan	250,000,000
Accordion Feature [Member]
Line Of Credit Facility [Line Items]
HCN Canadian Denomiated Term Loan	250,000,000
Financial Stand by Letter Of Credit [Member]
Line Of Credit Facility [Line Items]
Balance outstanding at quarter end	$ 61,882,247

[1] (1) As of June 30, 2015, letters of credit in the aggregate amount of $61,882,247 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.