Segment Information (Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information
Total capital expenditures	$ 607,296	$ 1,518,772	$ 728,641
Operating Segments | Triple-net leased properties
Segment Reporting Information
Total capital expenditures	42,930	55,429	58,744
Operating Segments | Senior living operations
Segment Reporting Information
Total capital expenditures	191,891	944,214	337,750
Operating Segments | Office operations
Segment Reporting Information
Total capital expenditures	$ 372,475	$ 519,129	$ 332,147