Credit Facility	6 Months Ended
	Jun. 30, 2020
Credit Facility [Abstract]
Credit Facility	5.Credit FacilityWe have a revolving credit agreement (the “Credit Facility”) with a $500 million borrowing limit, which matures on April 19, 2024. Amounts drawn on the Credit Facility bear annual interest at rates ranging from LIBOR plus 0.7% to LIBOR plus 1.350% depending upon the ratio of our Total Indebtedness to Gross Asset Value (as defined in the Credit Facility) (LIBOR plus 0.7% at June 30, 2020). We are also required to pay a quarterly facility fee ranging from 0.07% per annum to 0.25% per annum depending upon the ratio of our Total Indebtedness to our Gross Asset Value (0.07% per annum at June 30, 2020). At June 30, 2020 and August 5, 2020, we had no outstanding borrowings under this Credit Facility. We had undrawn standby letters of credit, which reduce our borrowing capacity, totaling $19.3 million at June 30, 2020 ($15.9 million at December 31, 2019). The Credit Facility has various customary restrictive covenants, all of which we were in compliance with at June 30, 2020.