Equity (Stock Transactions - Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended	0 Months Ended	1 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 At The Market Equity Offering Program [Member] investment_bank	Jul. 29, 2014 Subsequent Event [Member]	Jul. 31, 2014 Subsequent Event [Member] At The Market Equity Offering Program [Member]	Jun. 30, 2014 Minimum [Member] At The Market Equity Offering Program [Member]	Jun. 30, 2014 Maximum [Member] At The Market Equity Offering Program [Member]
Class of Stock [Line Items]
Issuance of common stock			$ 27,887
Net proceeds from issuance of common stock			$ 27,873	$ 132,416	$ 27,300		$ 7,200
Number of investment banks in sales agreements					4
Shares authorized to be sold under the program					9,000,000
Number of authorized shares remaining under offering program					4,291,100
Stock Issued During Period, Shares, New Issues					1,100,300		288,800
Dividends per share paid to common stockholders (in dollars per share)			$ 0.6
Dividends per share declared to common stockholders (in dollars per share)	$ 0.30	$ 0.30	$ 0.60	$ 0.60		$ 0.30
Shares Issued, Price Per Share								$ 24.48	$ 25.84