Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 Segment		Mar. 31, 2014		Dec. 31, 2014
Segment Information [Abstract]
Number of reportable segments	5
Segment Reporting Information [Line Items]
Revenue	$ 1,247,881		$ 747,275
Segment operating income	365,114	[1]	227,842	[1]
General and administrative (including non-cash stock-based compensation expense)	84,204		44,665
Facility lease expense	94,471		69,869
Depreciation and amortization	220,427		70,316
Transaction costs	6,742		10,844
Loss on facility lease termination	76,143		0
(Loss) Income from operations	(116,873)		32,148
Total assets	10,490,965				10,521,363
Retirement Centers [Member]
Segment Reporting Information [Line Items]
Revenue	163,486	[2]	132,349	[2]
Segment operating income	69,409	[1]	56,230	[1]
Total assets	1,601,789				1,603,704
Assisted Living [Member]
Segment Reporting Information [Line Items]
Revenue	617,344	[2]	277,431	[2]
Segment operating income	219,983	[1]	104,992	[1]
Total assets	6,538,732				6,513,376
Brookdale Ancillary Services [Member]
Segment Reporting Information [Line Items]
Revenue	115,411	[2]	63,417	[2]
Segment operating income	22,742	[1]	12,753	[1]
Total assets	247,340				224,229
CCRCs Rental [Member]
Segment Reporting Information [Line Items]
Revenue	155,991	[2]	97,944	[2]
Segment operating income	37,883	[1]	26,830	[1]
Total assets	1,100,344				1,065,116
CCRCs Entry Fee [Member]
Segment Reporting Information [Line Items]
Revenue	0	[2]	79,169	[2]
Segment operating income	0	[1]	19,635	[1]
Management Services [Member]
Segment Reporting Information [Line Items]
Revenue	195,649	[3]	96,965	[3]
Segment operating income	15,097	[1]	7,402	[1]
Total assets	$ 1,002,760				$ 1,114,938

[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.