Segment Information (Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information
Total capital expenditures	$ 1,683,110	$ 2,877,949	$ 1,662,728
Operating Segments | Triple-net leased properties
Segment Reporting Information
Total capital expenditures	74,192	1,890,245	647,870
Operating Segments | Senior living operations
Segment Reporting Information
Total capital expenditures	105,614	382,877	977,997
Operating Segments | Office operations
Segment Reporting Information
Total capital expenditures	$ 1,503,304	$ 604,827	$ 36,861