Acquisitions and Other Significant Transactions (Details)			1 Months Ended				3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	May. 01, 2015 USD ($) Community	Jun. 04, 2013 USD ($) Child	Oct. 31, 2015 USD ($) Community	Feb. 28, 2015 USD ($) Community	Aug. 31, 2014 USD ($) Community Unit Entity Property Member Representative	Jul. 31, 2014 USD ($) Community	Dec. 31, 2015 USD ($) Community shares	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Community shares	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Jun. 30, 2015 USD ($) Community	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Community shares	Dec. 31, 2014 USD ($) Community $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Jul. 30, 2014 shares
Business Acquisition [Line Items]
Percentage of voting interests acquired						100.00%
Number of communities operated under long-term leases | Community							546				583						546	583
Aggregate acquisition-date fair value of purchase consideration transferred						$ 3,000,000,000
Amount of mortgage indebtedness assumed						$ 1,400,000,000
Number of underlying communities with which mortgage loans collateralized | Community						179
Transaction costs of acquisition																	$ 8,252,000	$ 66,949,000	$ 3,921,000
Common stock, shares authorized (in shares) | shares							400,000,000				400,000,000						400,000,000	400,000,000		400
Number of venture transactions entered by the entity | Unit					2
Term of master agreement					15 years
Percentage of interest acquired in joint venture (in hundredths)					51.00%
Partners Joint Venture Ownership Percentage (in hundredths)					49.00%
Number of wholly-owned entities contributed to the venture by the entity | Entity					8
Number of communities owned by the entity | Community					8
Number of wholly-owned entities contributed to the venture by venture partner | Entity					3
Number of properties owned by venture partner | Property					3
Number of communities owned by venture partner | Community					2
Number of Communities Deconsolidated | Community																		10
Cash contributed to venture by venture partner					$ 323,500,000
Number of members on board | Member					6
Number of representatives on board | Representative					3
Number of communities under master lease and security agreement | Community					112
Number of communities under triple net leases agreement | Community					41
Number of pools under amended master leases agreement | Unit					3
Master leases term for Pool one communities					14 years
Master leases term for Pool two communities					15 years
Master leases term for Pool three communities					16 years
Number of extension options | Unit					2
Term of extension option					10 years
Base rent as per amended master leases agreement					$ 158,000,000
Maximum available reimbursement for capital expenditures by co venturer					$ 100,000,000
Initial lease rate for lessor reimbursements for capital expenditures (in hundredths)					7.00%
Number of communities for which purchase option included in master lease | Community					10
Maximum aggregate purchase price of communities under purchase option					$ 60,000,000
Number Of Communities With Cancelled Purchase Options | Community					49
Number of communities purchased or sold | Community																		4
Number of communities with modified term | Community					20
Extinguishment of Debt, Amount																		$ 275,900,000
Pro-forma consolidated operational data [Abstract]
Total revenue																		5,055,000,000	4,853,000,000
Net loss attributable to common shares																		$ (103,000,000)	$ (424,000,000)
Basic and diluted net loss per share attributable to common shares | $ / shares																		$ (0.59)	$ (2.48)
Weighted average shares used in computing basic and diluted net loss per share (in shares) | shares																		175,823	171,255
Loss on facility lease termination																	$ 76,143,000	$ 0	$ 0
Asset impairment							$ 57,941,000	$ 0	$ 0	$ 0	$ 9,992,000	$ 0	$ 0	$ 0			57,941,000	9,992,000	12,891,000
Aggregate selling price																	82,900,000	9,200,000
Assets Held-for-sale							110,620,000				0						110,620,000	0
Long-term debt, less current portion							$ 3,459,371,000				3,340,971,000						$ 3,459,371,000	3,340,971,000
Communities classified as held for sale | Community							17										17
Partners Joint Venture Ownership Percentage					49.00%
Investment in unconsolidated ventures																	$ (69,297,000)	(26,499,000)	(17,172,000)
Loss Contingencies [Line Items]
Number of adult children of Joan Boice | Child		3
Attorney fees awarded to plaintiffs' lawyer		$ 4,100,000
Cash deposit made to collateralize the bond		20,900,000
Stockholders' Equity Note [Abstract]
Stock Issued During Period, Shares, New Issues | shares																	10,298,506
Proceeds from public equity offering, net																	$ 0	330,386,000	0
Deferred Offering Costs											$ 400,000							$ 400,000
Weighted average interest rate											5.50%							5.50%
Extinguishment of Debt, Amount																		$ 275,900,000
Common stock issued in connection with Emeritus acquisition																		$ 1,648,782,000
Stock Issued During Period, Shares, Acquisitions | shares																		47,584,000
CCRCs JV [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community					4
RIDEA JV [Member]
Business Acquisition [Line Items]
Percentage of interest acquired in joint venture (in hundredths)					20.00%
Partners Joint Venture Ownership Percentage (in hundredths)					80.00%
Advance from co venturers affiliate					$ 68,000,000
Number of communities contributed by venture partner | Community					49
Lease restructuring fee payable to co venturer					$ 34,000,000
Period with in which lease restructuring fee payable					2 years
Extinguishment of Debt, Amount																		$ 68,000,000
Pro-forma consolidated operational data [Abstract]
Partners Joint Venture Ownership Percentage					80.00%
Stockholders' Equity Note [Abstract]
Extinguishment of Debt, Amount																		68,000,000
Minimum [Member]
Business Acquisition [Line Items]
Weighted average interest rate (in hundredths)						5.49%
Debt maturity period						3 months
Maximum [Member]
Business Acquisition [Line Items]
Weighted average interest rate (in hundredths)						6.06%
Debt maturity period						33 years
Punitive damages [Member]
Loss Contingencies [Line Items]
Damages to be paid		23,000,000
Compensatory damages [Member]
Loss Contingencies [Line Items]
Damages to be paid		$ 250,000
Retirement Centers [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community						3
Preliminary Allocation of Purchase Price [Abstract]
Goodwill acquired during period																		20,499,000
Assisted Living [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community						1
Preliminary Allocation of Purchase Price [Abstract]
Goodwill acquired during period																		497,900,000
Brookdale Ancillary Services [Member]
Preliminary Allocation of Purchase Price [Abstract]
Goodwill acquired during period																		126,810,000
Emeritus [Member]
Business Acquisition [Line Items]
Number of communities operated | Community						493
Number of communities operated under long-term leases | Community						311
Transaction costs of acquisition																		57,100,000
Number of communities owned by the entity | Community						182
Preliminary Allocation of Purchase Price [Abstract]
Cash and cash equivalents							$ 28,000,000										28,000,000
Property, plant and equipment and leasehold intangibles							5,506,000,000										5,506,000,000
Goodwill acquired during period																		$ 645,000
Other intangible assets, net							259,000,000										259,000,000
Other assets, net							307,000,000										307,000,000
Trade Accounts Payable and accrued expenses							(297,000,000)										(297,000,000)
Long-term debt							(1,516,000,000)										(1,516,000,000)
Capital and Financing Lease obligations							(2,692,000,000)										(2,692,000,000)
Deferred tax liability							(339,000,000)										(339,000,000)
Other liabilities							(251,000,000)										(251,000,000)
Noncontrolling interest							(1,000,000)										(1,000,000)
Fair value of Brookdale common stock issued							$ 1,649,000,000										$ 1,649,000,000
Pro-forma consolidated operational data [Abstract]
Goodwill, Purchase Accounting Adjustments																$ 5,900,000
Acquisition of Communities [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community						4
Aggregate purchase price						$ 51,400,000
Acquisition purchase price amount financed						$ 17,000,000
Number of communities securing acquisition financing | Community						3
Acquired property plant and equipment [Member] | Minimum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate						5.50%
Acquired property plant and equipment [Member] | Maximum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate						9.75%
Acquired capital and financing lease obligations [Member] | Minimum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate						6.00%
Acquired capital and financing lease obligations [Member] | Maximum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate						10.75%
Acquired long-term debt obligations [Member] | Minimum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate						3.00%
Acquired long-term debt obligations [Member] | Maximum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate						7.00%
SellerFinanced Debt [Member]
Pro-forma consolidated operational data [Abstract]
LoanTerm																	5 years
Seller financing fixed rate							8.00%										8.00%
Principal							$ 20,000,000										$ 20,000,000
Acquisition of Venture Interest [Member]
Business Acquisition [Line Items]
Partners Joint Venture Ownership Percentage (in hundredths)									10.00%						10.00%
Number of communities purchased or sold | Community															35
Aggregate purchase price															$ 847,000,000
Pro-forma consolidated operational data [Abstract]
Partners Joint Venture Ownership Percentage									10.00%						10.00%
Investment in unconsolidated ventures															$ 30,300,000
February 2015 acquisition of 15 communities [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community				15
Aggregate purchase price				$ 268,600,000
Pro-forma consolidated operational data [Abstract]
Fair Value of Assets Acquired				187,200,000
Reversal of deferred lease liability				5,300,000
Loss on facility lease termination				$ 76,100,000
February 2015 acquisition of 15 communities [Member] | Minimum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate				6.25%
February 2015 acquisition of 15 communities [Member] | Maximum [Member]
Pro-forma consolidated operational data [Abstract]
Fair Value Inputs, Cap Rate				8.75%
5 Communities acquired in October 2015 [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community			5
Aggregate purchase price			$ 78,400,000
Communities sold during 2015 [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community																	17
Pro-forma consolidated operational data [Abstract]
Asset impairment																	$ 18,400,000
Aggregate selling price																	82,900,000
HCP Community Acquisitions [Member]
Business Acquisition [Line Items]
Number of communities purchased or sold | Community	1																	9
Aggregate purchase price	$ 8,600,000																	$ 60,000,000
Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Pro-forma consolidated operational data [Abstract]
Asset impairment																	15,172,000	0	0
Assets Held-for-sale							110,620,000				$ 0						110,620,000	$ 0	$ 0
Long-term debt, less current portion							$ 60,800,000										$ 60,800,000