EQUITY ATM Equity Program (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 At The Market Equity Program	Jun. 30, 2014 At The Market Equity Program	Jun. 30, 2014 Commissions At The Market Equity Program	Jun. 30, 2014 Commissions At The Market Equity Program	Jun. 30, 2014 Other Offering Costs At The Market Equity Program	Jun. 30, 2014 Other Offering Costs At The Market Equity Program
Equity [Line Items]
Number of shares of common stock issued through ATM program			675,270	2,110,485
Weighted average price per share			$ 34.46	$ 33.51
Proceeds, gross			$ 23,266	$ 70,713
Payments of stock issuance costs					(233)	(708)	(51)	(96)
Proceeds, net	$ 69,909	$ 24,922	$ 22,982	$ 69,909