Investments in Unconsolidated Entity (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2019
Investments in Unconsolidated Joint Ventures
Assets	$ 4,085,290	$ 3,898,572
Liabilities	2,295,610	2,313,874
Joint venture with Alinda
Investments in Unconsolidated Joint Ventures
Equity method investments	$ 25,900	22,600
Ownership interest (as a percent)	50.00%
Joint venture with Alinda
Investments in Unconsolidated Joint Ventures
Lease term of facility with global cloud-based software company			10 years
Assets	$ 145,800	141,500
Liabilities	$ 92,200	$ 90,100