Debt (Details) (Key Bank Credit Facility, Revolving Credit Facility, USD $)
0 Months Ended
Dec. 12, 2014
Dec. 12, 2014
Line of Credit Facility [Line Items]    
Line of Credit Facility, Current Borrowing Capacity $ 250,000,000.0 $ 250,000,000.0
Line of Credit Facility, Maximum Borrowing Capacity 1,250,000,000.00 1,250,000,000.00
Debt Instrument, Collateral Percent 100.00% 100.00%
Minimum Net Worth Required for Compliance, Percent 80.00% 80.00%
Minimum Net Worth Required for Compliance 4,700,000.0 4,700,000.0
Net Future Equity Issuances Required for Compliance, Percent 75.00% 75.00%
Debt Instrument, Covenant, Fixed Charge Coverage Ratio, Minimum 1.50 1.50
Debt Instrument, Covenant, Secured Debt Ratio, Maximum 40.00% 40.00%
Debt Instrument, Covenant, Increase in Maximum Secured Debt Ratio for One Year After Closing of a Material Acquisition, Percentage Points 5.00% 5.00%
Debt Instrument, Covenant, Secured Recourse Debt Ratio, Maximum 10.00% 10.00%
Debt Instrument, Covenant Compliance, Threshold For Tangible Net Worth $ 250,000,000 $ 250,000,000
Debt Instrument, Maximum Unhedged Variable Rate 30.00%  
Debt Instrument, Covenant, Payout Ratio, Maximum 95.00% 95.00%
Federal Funds Rate
   
Line of Credit Facility [Line Items]    
Debt Instrument, Basis Spread on Variable Rate 0.50%  
Minimum    
Line of Credit Facility [Line Items]    
Debt Instrument, Covenant, Leverage Ratio, Maximum 60.00% 60.00%
Maximum    
Line of Credit Facility [Line Items]    
Debt Instrument, Covenant, Leverage Ratio, Maximum 65.00% 65.00%