Segment Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) Segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Segment Information [Abstract]
Number of reportable segments | Segment				5
Segment Reporting Information [Line Items]
Revenue		$ 1,238,841	$ 1,083,935	$ 3,724,906	$ 2,579,603
Segment operating income	[1]	355,056	328,856	1,089,322	782,289
General and administrative (including non-cash stock-based compensation expense)		99,534	90,020	278,609	181,693
Transaction costs		0	41,572	7,163	59,224
Facility lease expense		91,144	91,462	276,953	231,361
Depreciation and amortization		160,715	178,999	606,787	320,403
Loss on facility lease termination		0	0	76,143	0
Income (loss) from operations		3,663	(73,197)	(156,333)	(10,392)
Total assets		10,274,960		10,274,960		$ 10,521,363
Retirement Centers [Member]
Segment Reporting Information [Line Items]
Revenue	[2]	164,415	155,227	492,310	421,017
Segment operating income	[1]	70,334	67,205	212,902	180,326
Total assets		1,609,486		1,609,486		1,607,792
Assisted Living [Member]
Segment Reporting Information [Line Items]
Revenue	[2]	608,393	516,640	1,837,575	1,071,301
Segment operating income	[1]	211,213	188,154	658,078	397,392
Total assets		6,466,083		6,466,083		6,584,830
Brookdale Ancillary Services [Member]
Segment Reporting Information [Line Items]
Revenue	[2]	117,702	95,426	349,283	224,377
Segment operating income	[1]	17,420	18,146	57,886	43,804
Total assets		295,141		295,141		275,618
CCRCs Rental [Member]
Segment Reporting Information [Line Items]
Revenue	[2]	149,572	144,074	457,124	340,230
Segment operating income	[1]	41,395	34,492	115,826	87,015
Total assets		1,051,371		1,051,371		1,062,828
CCRCs Entry Fee [Member]
Segment Reporting Information [Line Items]
Revenue	[2]	0	44,145	0	202,414
Segment operating income	[1]	0	10,431	0	48,433
Management Services [Member]
Segment Reporting Information [Line Items]
Revenue	[3]	198,759	128,423	588,614	320,264
Segment operating income	[1]	14,694	$ 10,428	44,630	$ 25,319
Total assets		$ 852,879		$ 852,879		$ 990,295

[1] Segment operating income is defined as segment revenues less segment operating expenses (excluding depreciation and amortization).

[2] All revenue is earned from external third parties in the United States.

[3] Management services segment revenue includes reimbursements for which the Company is the primary obligor of costs incurred on behalf of managed communities.