Indebtedness	3 Months Ended
Mar. 31, 2013
Indebtedness
Indebtedness	Note 6. Indebtedness Our principal debt obligations at March 31, 2013 were: our (1) $750,000 unsecured revolving credit facility; (2) four public issuances of unsecured senior notes, including: (a) $250,000 principal amount due 2016 at an annual interest rate of 4.30%, (b) $200,000 principal amount due 2020 at an annual interest rate of 6.75%, (c) $300,000 principal amount due 2021 at an annual interest rate of 6.75% and (d) $350,000 principal amount due 2042 at an annual interest rate of 5.625%; and (3) $714,439 aggregate principal amount of mortgages secured by 57 of our properties with maturity dates from 2013 to 2043. The 57 mortgaged properties had a carrying value of $983,479 at March 31, 2013. We also have two properties subject to capital leases totaling $13,676 at March 31, 2013; these two properties had a carrying value of $18,124 at March 31, 2013. In connection with the acquisitions discussed in Note 3 above, during the three months ended March 31, 2013, we assumed $12,266 of mortgage debt, which was recorded at a fair value of $13,306. This mortgage has a contractual interest rate of 6.25% and matures in May 2015. We recorded the assumed mortgage at its fair value, which exceeded its outstanding principal balance by $1,040. We determined the fair value of the assumed mortgages using a market approach based upon Level 3 inputs (significant other unobservable inputs) in the fair value hierarchy. We have a $750,000 unsecured revolving credit facility that is available for general business purposes, including acquisitions. The maturity date of our revolving credit facility is June 24, 2015 and, subject to the payment of an extension fee and meeting certain other conditions, includes an option for us to extend the stated maturity date of our revolving credit facility by one year to June 24, 2016. In addition, our revolving credit facility includes a feature under which maximum borrowings may be increased to up to $1,500,000 in certain circumstances. Borrowings under our revolving credit facility bear interest at LIBOR plus a premium, which was 160 basis points as of March 31, 2013. We also pay a facility fee of 35 basis points per annum on the total amount of lending commitments under our revolving credit facility. Both the interest rate premium and the facility fee are subject to adjustment based upon changes to our credit ratings. We can borrow, repay and reborrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. The weighted average annual interest rate for borrowings under our revolving credit facility was 1.7% for the three months ended March 31, 2013. We incurred interest expense and other associated costs related to our revolving credit facility of $231 for the three months ended March 31, 2013. As of March 31, 2013, we had no borrowings outstanding and $750,000 available under our revolving credit facility.

Note 6. Indebtedness

Our principal debt obligations at March 31, 2013 were: our (1) $750,000 unsecured revolving credit facility; (2) four public issuances of unsecured senior notes, including: (a) $250,000 principal amount due 2016 at an annual interest rate of 4.30%, (b) $200,000 principal amount due 2020 at an annual interest rate of 6.75%, (c) $300,000 principal amount due 2021 at an annual interest rate of 6.75% and (d) $350,000 principal amount due 2042 at an annual interest rate of 5.625%; and (3) $714,439 aggregate principal amount of mortgages secured by 57 of our properties with maturity dates from 2013 to 2043. The 57 mortgaged properties had a carrying value of $983,479 at March 31, 2013. We also have two properties subject to capital leases totaling $13,676 at March 31, 2013; these two properties had a carrying value of $18,124 at March 31, 2013.

In connection with the acquisitions discussed in Note 3 above, during the three months ended March 31, 2013, we assumed $12,266 of mortgage debt, which was recorded at a fair value of $13,306. This mortgage has a contractual interest rate of 6.25% and matures in May 2015. We recorded the assumed mortgage at its fair value, which exceeded its outstanding principal balance by $1,040. We determined the fair value of the assumed mortgages using a market approach based upon Level 3 inputs (significant other unobservable inputs) in the fair value hierarchy.

We have a $750,000 unsecured revolving credit facility that is available for general business purposes, including acquisitions. The maturity date of our revolving credit facility is June 24, 2015 and, subject to the payment of an extension fee and meeting certain other conditions, includes an option for us to extend the stated maturity date of our revolving credit facility by one year to June 24, 2016. In addition, our revolving credit facility includes a feature under which maximum borrowings may be increased to up to $1,500,000 in certain circumstances. Borrowings under our revolving credit facility bear interest at LIBOR plus a premium, which was 160 basis points as of March 31, 2013. We also pay a facility fee of 35 basis points per annum on the total amount of lending commitments under our revolving credit facility. Both the interest rate premium and the facility fee are subject to adjustment based upon changes to our credit ratings. We can borrow, repay and reborrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. The weighted average annual interest rate for borrowings under our revolving credit facility was 1.7% for the three months ended March 31, 2013. We incurred interest expense and other associated costs related to our revolving credit facility of $231 for the three months ended March 31, 2013. As of March 31, 2013, we had no borrowings outstanding and $750,000 available under our revolving credit facility.