Leases	9 Months Ended
Leases	Sep. 30, 2021
Leases [Abstract]
Leases	Leases Our leases provide for base rent payments and in addition may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term when we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the tenant to meet its lease obligations; we have determined the fixed non-cancelable lease term of these leases to be the full term of the lease because we believe the occurrence of early terminations to be a remote contingency based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis. We increased rental income to record revenue on a straight line basis by $3,924 and $3,912 for the three months ended September 30, 2021 and 2020, respectively, and $13,128 and $12,963 for the nine months ended September 30, 2021 and 2020, respectively. Rents receivable, excluding properties classified as held for sale, include $76,033 and $68,824 of straight line rent receivables at September 30, 2021 and December 31, 2020, respectively. We do not include in our measurement of our lease receivables certain variable payments, including payments determined by changes in the index or market-based indices after the inception of the lease, certain tenant reimbursements and other income until the specific events that trigger the variable payments have occurred. Such payments totaled $24,098 and $60,446 for the three and nine months ended September 30, 2021, respectively, of which tenant reimbursements totaled $23,167 and $57,609, respectively. For the three and nine months ended September 30, 2020, such payments totaled $18,606 and $56,654, respectively, of which tenant reimbursements totaled $17,495 and $53,346, respectively.
Leases	Leases Our leases provide for base rent payments and in addition may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term when we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the tenant to meet its lease obligations; we have determined the fixed non-cancelable lease term of these leases to be the full term of the lease because we believe the occurrence of early terminations to be a remote contingency based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis. We increased rental income to record revenue on a straight line basis by $3,924 and $3,912 for the three months ended September 30, 2021 and 2020, respectively, and $13,128 and $12,963 for the nine months ended September 30, 2021 and 2020, respectively. Rents receivable, excluding properties classified as held for sale, include $76,033 and $68,824 of straight line rent receivables at September 30, 2021 and December 31, 2020, respectively. We do not include in our measurement of our lease receivables certain variable payments, including payments determined by changes in the index or market-based indices after the inception of the lease, certain tenant reimbursements and other income until the specific events that trigger the variable payments have occurred. Such payments totaled $24,098 and $60,446 for the three and nine months ended September 30, 2021, respectively, of which tenant reimbursements totaled $23,167 and $57,609, respectively. For the three and nine months ended September 30, 2020, such payments totaled $18,606 and $56,654, respectively, of which tenant reimbursements totaled $17,495 and $53,346, respectively.