Segment Information (Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information
Total capital expenditures	$ 728,641	$ 1,096,327	$ 1,667,593
Operating Segments | Triple Net Leased Properties
Segment Reporting Information
Total capital expenditures	58,744	254,542	74,192
Operating Segments | Senior Living Operations
Segment Reporting Information
Total capital expenditures	337,750	261,900	105,614
Operating Segments | Office Operations
Segment Reporting Information
Total capital expenditures	$ 332,147	$ 579,885	$ 1,487,787