Related Party Transactions (Debt Agreements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Related Party [Line Items]
Current Principle Amount	$ 1,384,000
Opening Principle Amount		$ 1,711,000
Prudential Financial Loan 1
Related Party [Line Items]
Current Principle Amount	$ 0
Opening Principle Amount		50,000
Interest Rate	2.64%
Prudential Financial Loan 2
Related Party [Line Items]
Current Principle Amount	$ 11,000
Opening Principle Amount		11,000
Interest Rate	3.61%
Prudential Financial Loan 3
Related Party [Line Items]
Current Principle Amount	$ 11,000
Opening Principle Amount		22,000
Interest Rate Near	3.32%
Interest Rate Far	3.61%
Prudential Insurance Loan 1
Related Party [Line Items]
Current Principle Amount	$ 0
Opening Principle Amount		204,000
Interest Rate	3.47%
Washington Street Loan 1
Related Party [Line Items]
Current Principle Amount	$ 0
Opening Principle Amount		237,000
Interest Rate Near	2.44%
Interest Rate Far	3.02%
Washington Street Loan 2
Related Party [Line Items]
Current Principle Amount	$ 0
Opening Principle Amount		198,000
Interest Rate Near	1.33%
Interest Rate Far	1.87%
Washington Street Loan 3
Related Party [Line Items]
Current Principle Amount	$ 0
Opening Principle Amount		39,000
Interest Rate Near	1.33%
Interest Rate Far	1.87%
Prudential Financial Loan 5
Related Party [Line Items]
Current Principle Amount	$ 9,000
Opening Principle Amount		9,000
Interest Rate	2.24%
Prudential Financial Loan 6
Related Party [Line Items]
Current Principle Amount	$ 23,000
Opening Principle Amount		23,000
Interest Rate	3.19%
Prudential Insurance Loan 2
Related Party [Line Items]
Current Principle Amount	$ 120,000
Opening Principle Amount		120,000
Interest Rate	2.60%
Prudential Insurance Loan 3
Related Party [Line Items]
Current Principle Amount	$ 130,000
Opening Principle Amount		130,000
Interest Rate	4.39%
Prudential Insurance Loan 4
Related Party [Line Items]
Current Principle Amount	$ 250,000
Opening Principle Amount		250,000
Interest Rate	3.64%
Prudential Insurance Loan 5
Related Party [Line Items]
Current Principle Amount	$ 30,000
Opening Principle Amount		30,000
Interest Rate	1.89%
Prudential Insurance Loan 6
Related Party [Line Items]
Current Principle Amount	$ 40,000
Opening Principle Amount		40,000
Interest Rate	3.95%
Prudential Insurance Loan 7
Related Party [Line Items]
Current Principle Amount	$ 20,000
Opening Principle Amount		20,000
Interest Rate	2.80%
Prudential Insurance Loan 8
Related Party [Line Items]
Current Principle Amount	$ 50,000
Opening Principle Amount		50,000
Interest Rate	3.95%
Prudential Insurance Loan 9
Related Party [Line Items]
Current Principle Amount	$ 50,000
Opening Principle Amount		50,000
Interest Rate	2.80%
Prudential Insurance Loan 10
Related Party [Line Items]
Current Principle Amount	$ 100,000
Opening Principle Amount		100,000
Interest Rate	3.47%
Prudential Insurance Loan 11
Related Party [Line Items]
Current Principle Amount	$ 100,000
Opening Principle Amount		100,000
Interest Rate	3.95%
Prudential Financial Loan 7
Related Party [Line Items]
Current Principle Amount	$ 5,000
Opening Principle Amount		5,000
Interest Rate	2.57%
Prudential Financial Loan 8
Related Party [Line Items]
Current Principle Amount	$ 23,000
Opening Principle Amount		23,000
Interest Rate	3.14%
Prudential Financial Loan 9
Related Party [Line Items]
Current Principle Amount	$ 66,000
Opening Principle Amount		0
Interest Rate	3.52%
Prudential Financial Loan 10
Related Party [Line Items]
Current Principle Amount	$ 6,000
Opening Principle Amount		0
Interest Rate	2.86%
Prudential Financial Loan 11
Related Party [Line Items]
Current Principle Amount	$ 158,000
Opening Principle Amount		0
Interest Rate Near	1.09%
Interest Rate Far	1.63%
Prudential Financial Loan 12
Related Party [Line Items]
Current Principle Amount	$ 132,000
Opening Principle Amount		0
Interest Rate Near	1.40%
Interest Rate Far	1.93%
Prudential Financial Loan 13
Related Party [Line Items]
Current Principle Amount	$ 26,000
Opening Principle Amount		0
Interest Rate Near	1.40%
Interest Rate Far	1.93%
Prudential Financial Loan 14
Related Party [Line Items]
Current Principle Amount	$ 5,000
Opening Principle Amount		0
Interest Rate	2.85%
Prudential Financial Loan 15
Related Party [Line Items]
Current Principle Amount	$ 1,000
Opening Principle Amount		0
Interest Rate	2.85%
Prudential Financial Loan 16
Related Party [Line Items]
Current Principle Amount	$ 18,000
Opening Principle Amount		$ 0
Interest Rate	3.37%