Forward Equity	3 Months Ended
Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Forward Equity Sales	Forward Equity Under the Company's 2012 forward equity agreement, it had outstanding contracts as of December 31, 2013 to sell a notional amount of $70.2 million at an average share price of $123.09. During the three months ended March 31, 2014, the Company agreed to net settle $15.1 million notional amount for cash at an average share price of $199.19. In April 2014, the Company agreed to net settle all remaining outstanding contracts for cash at an average share price of $198.58. The Company has $252.8 million remaining notional amount that it may elect to sell under the forward equity agreement.

Forward Equity

3 Months Ended

Mar. 31, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Forward Equity

Under the Company's 2012 forward equity agreement, it had outstanding contracts as of December 31, 2013 to sell a notional amount of $70.2 million at an average share price of $123.09. During the three months ended March 31, 2014, the Company agreed to net settle $15.1 million notional amount for cash at an average share price of $199.19. In April 2014, the Company agreed to net settle all remaining outstanding contracts for cash at an average share price of $198.58. The Company has $252.8 million remaining notional amount that it may elect to sell under the forward equity agreement.