Other Real Estate Property Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real estate acquisitions
Consideration, Cash Paid/Debt Settled	$ 560,753	$ 467,162
Consideration, Net Liabilities Assumed	5,425	82,985
Assets Acquired, Real Estate	527,815	522,600
Assets Acquired, Net Intangibles	38,363	27,547
Funding for construction, tenant and other capital improvements	471,778	458,900	$ 384,782
Senior housing triple-net
Real estate acquisitions
Consideration, Cash Paid/Debt Settled		76,362
Consideration, Net Liabilities Assumed		1,200
Assets Acquired, Real Estate		71,875
Assets Acquired, Net Intangibles		5,687
Funding for construction, tenant and other capital improvements	32,343	49,109	53,980
SHOP
Real estate acquisitions
Consideration, Cash Paid/Debt Settled	44,258	113,971
Consideration, Net Liabilities Assumed	797	76,931
Assets Acquired, Real Estate	37,940	177,551
Assets Acquired, Net Intangibles	7,115	13,351
Funding for construction, tenant and other capital improvements	49,473	74,158	77,425
Life science
Real estate acquisitions
Consideration, Cash Paid/Debt Settled	315,255	49,000
Consideration, Net Liabilities Assumed	3,524	0
Assets Acquired, Real Estate	305,760	47,400
Assets Acquired, Net Intangibles	13,019	1,600
Funding for construction, tenant and other capital improvements	240,901	200,122	122,319
Medical office
Real estate acquisitions
Consideration, Cash Paid/Debt Settled	201,240	209,920
Consideration, Net Liabilities Assumed	1,104	4,854
Assets Acquired, Real Estate	184,115	209,178
Assets Acquired, Net Intangibles	18,229	5,596
Funding for construction, tenant and other capital improvements	148,926	128,308	131,021
Other non-reportable segments
Real estate acquisitions
Consideration, Cash Paid/Debt Settled		17,909
Consideration, Net Liabilities Assumed		0
Assets Acquired, Real Estate		16,596
Assets Acquired, Net Intangibles		1,313
Funding for construction, tenant and other capital improvements	$ 135	$ 7,203	$ 37