Debt (Narrative) (Details) (USD $)			9 Months Ended			9 Months Ended											9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Maximum [Member]	Sep. 30, 2014 Minimum [Member]	May 31, 2013 Outdated Unsecured Short Term Revolving Credit Facility [Member]	Sep. 30, 2014 Amended And Restated Unsecured Short Term Revolving Credit Facility [Member]	Sep. 30, 2014 Minimum Credit Spread On LIBOR Or CDOR Borrowings [Member]	Sep. 30, 2014 Maximum Credit Spread On LIBOR Or CDOR Borrowings [Member]	Sep. 30, 2014 Maximum Credit Spread On Prime Rate Borrowings [Member]	Jul. 21, 2014 Senior Notes [Member]	Dec. 31, 2013 Senior Notes [Member]	Jul. 21, 2014 Series A Senior Note [Member]	Dec. 31, 2013 Series A Senior Note [Member]	Jul. 21, 2014 Series B Senior Note [Member]	Dec. 31, 2013 Series B Senior Note [Member]	Jul. 22, 2014 NYL Note [Member]	Sep. 30, 2014 Senior Note Agreement [Member]
Line of Credit Facility [Line Items]
Borrowing capacity					$ 450,000,000	$ 700,000,000
Credit Facility maturity date						Jun. 18, 2019
Outstanding Credit Facility balance	375,000,000	277,000,000
Credit Facility weighted average interest rates on outstanding balance	1.60%	1.60%
Reduction of Credit Facility Availability	1,000,000
Credit spread during period							0.875%	1.375%	0.375%
Credit Facility borrowings hedged	80,000,000
Commitment fees			0.35%	0.15%
Consolidated Leverage Ratio Under Credit Facility & Note Payable, maximum																	3.5
Notes Payable										$ 125,000,000	$ 150,000,000	$ 50,000,000	$ 75,000,000	$ 75,000,000	$ 75,000,000	$ 75,000,000
Debt Instrument, Interest Rate, Stated Percentage												3.32%	3.94%	3.76%	4.04%	3.72%