CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Rental income:
Triple-net leased	$ 840,131	$ 845,834	$ 779,801
Office	753,467	630,342	566,245
Total rental income	1,593,598	1,476,176	1,346,046
Resident fees and services	1,843,232	1,847,306	1,811,255
Office building and other services revenue	13,677	21,070	41,492
Income from loans and investments	117,608	98,094	86,553
Interest and other income	6,034	876	1,052
Total revenues	3,574,149	3,443,522	3,286,398
Expenses
Interest	448,196	419,740	367,114
Depreciation and amortization	887,948	898,924	894,057
Property-level operating expenses:
Senior living	1,250,065	1,242,978	1,209,415
Office	233,007	191,784	174,225
Property-level operating expenses	1,483,072	1,434,762	1,383,640
Office building services costs	3,391	7,311	26,565
General, administrative and professional fees	135,490	126,875	128,035
Loss on extinguishment of debt, net	754	2,779	14,411
Merger-related expenses and deal costs	10,535	24,635	102,944
Other	20,052	9,988	17,957
Total expenses	2,989,438	2,925,014	2,934,723
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interests	584,711	518,508	351,675
(Loss) income from unconsolidated entities	(561)	4,358	(1,420)
Income tax benefit	59,799	31,343	39,284
Income from continuing operations	643,949	554,209	389,539
Discontinued operations	(110)	(922)	11,103
Gain on real estate dispositions	717,273	98,203	18,580
Net income	1,361,112	651,490	419,222
Net income attributable to noncontrolling interests	4,642	2,259	1,379
Net income attributable to common stockholders	$ 1,356,470	$ 649,231	$ 417,843
Basic:
Income from continuing operations (USD per share)	$ 1.81	$ 1.61	$ 1.18
Net income attributable to common stockholders (USD per share)	3.82	1.88	1.26
Diluted:
Income from continuing operations (USD per share)	1.80	1.59	1.17
Net income attributable to common stockholders (USD per share)	$ 3.78	$ 1.86	$ 1.25
Weighted average shares used in computing earnings per common share:
Basic (in shares)	355,326	344,703	330,311
Diluted (in shares)	358,566	348,390	334,007