Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 Segment		Dec. 31, 2013		Dec. 31, 2012
Segment Information [Abstract]
Number of reportable segments									5
Segment Reporting Information [Line Items]
Revenues	$ 1,252,103	$ 1,083,935	$ 748,393	$ 747,275	$ 734,233	$ 728,999	$ 716,468	$ 712,266	$ 3,831,706		$ 2,891,966		$ 2,768,738
Segment operating income									1,133,168		874,213		812,803
General and administrative (including non-cash stock-based compensation expense)									280,267		180,627		178,829
Facility lease expense									323,830		276,729		284,025
Depreciation and amortization									537,035		268,757		252,281
Asset impairment	9,992	0	0	0	10,233	504	2,154	0	9,992		12,891		27,677
Loss on acquisition									0		0		636
Gain on facility lease termination									0		0		(11,584)
Income from operations	(74,513)	(73,197)	30,657	32,148	30,183	33,983	28,435	38,687	(84,905)		131,288		80,939
Total interest expense									248,188		137,399		146,783
Total expenditures for property, plan and equipment, and leasehold improvements									304,245		257,527		208,412
Assets by segment	10,521,363				4,737,757				10,521,363		4,737,757
Retirement Centers [Member]
Segment Reporting Information [Line Items]
Revenues									582,312	[1]	526,284	[1]	503,902	[1]
Segment operating income									248,883	[2]	222,282	[2]	205,585	[2]
Facility lease expense									98,321		91,258		102,273
Depreciation and amortization									86,188		64,353		61,060
Total interest expense									41,906		31,286		29,025
Total expenditures for property, plan and equipment, and leasehold improvements									76,285		63,519		58,876
Assets by segment	1,603,704				1,258,294				1,603,704		1,258,294
Assisted Living [Member]
Segment Reporting Information [Line Items]
Revenues									1,685,563	[1]	1,051,868	[1]	1,013,337	[1]
Segment operating income									608,489	[2]	389,678	[2]	361,184	[2]
Facility lease expense									162,575		123,980		123,128
Depreciation and amortization									317,918		85,337		81,801
Total interest expense									140,001		51,410		57,634
Total expenditures for property, plan and equipment, and leasehold improvements									107,037		95,829		68,675
Assets by segment	6,513,376				1,514,385				6,513,376		1,514,385
CCRCs Rental [Member]
Segment Reporting Information [Line Items]
Revenues									493,173	[1]	396,975	[1]	385,479	[1]
Segment operating income									121,661	[2]	109,026	[2]	106,063	[2]
Facility lease expense									51,523		48,809		47,238
Depreciation and amortization									60,175		30,957		31,205
Total interest expense									28,418		17,512		17,336
Total expenditures for property, plan and equipment, and leasehold improvements									42,412		27,134		21,916
Assets by segment	1,065,116				499,873				1,065,116		499,873
CCRCs Entry Fee [Member]
Segment Reporting Information [Line Items]
Revenues									202,414	[1]	297,756	[1]	285,701	[1]
Segment operating income									48,433	[2]	76,393	[2]	61,405	[2]
Facility lease expense									4,362		7,470		7,214
Depreciation and amortization									37,524		55,842		52,840
Total interest expense									7,530		11,911		13,792
Total expenditures for property, plan and equipment, and leasehold improvements									36,575		43,019		24,890
Assets by segment	0				960,708				0		960,708
Brookdale Ancillary Services [Member]
Segment Reporting Information [Line Items]
Revenues									337,835	[1]	242,150	[1]	224,517	[1]
Segment operating income									63,463	[2]	45,709	[2]	47,780	[2]
Facility lease expense									890		0		0
Depreciation and amortization									4,764		3,023		2,220
Total interest expense									823		0		0
Total expenditures for property, plan and equipment, and leasehold improvements									1,805		1,855		6,037
Assets by segment	224,229				94,986				224,229		94,986
Management Services [Member]
Segment Reporting Information [Line Items]
Revenues									530,409	[1],[3]	376,933	[1],[3]	355,802	[1],[3]
Segment operating income									42,239	[2]	31,125	[2]	30,786	[2]
Facility lease expense									6,159		5,212		4,172
Depreciation and amortization									30,466		29,245		23,155
Total interest expense									29,510		25,280		28,996
Total expenditures for property, plan and equipment, and leasehold improvements									40,131		26,171		28,018
Assets by segment	$ 1,114,938				$ 409,511				$ 1,114,938		$ 409,511

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

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

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