CONSOLIDATED STATEMENTS OF CASH FLOWS - Cash and Restricted Cash (Parenthetical) $ in Thousands		Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Statement of Cash Flows [Abstract]
Cash and cash equivalents		$ 74,417	$ 37,357	$ 54,976
Restricted cash	[1]	16,432	14,867	15,095
Total cash and cash equivalents and restricted cash shown in our consolidated statements of cash flows		$ 90,849	$ 52,224	$ 70,071	$ 47,321
Number of properties owned (property) | property		397
Life Science Property | Joint venture
Number of properties owned (property) | property		1
Equity method investment ownership percentage		55.00%

[1] Restricted cash consists of amounts escrowed for real estate taxes, insurance and capital expenditures at certain of our mortgaged properties and cash held for the operations of one of our life science properties that is owned in a joint venture arrangement in which we own a 55% equity interest.