Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net income	$ 577,146	$ 131,159
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	171,094	164,594
Amortization of right of use assets - operating leases	583	605
Impairment loss	0	24,038
Non-cash compensation expense	17,525	15,050
Loss (income) from unconsolidated joint ventures	369	(213)
Distributions of net cash flow from operations of unconsolidated joint ventures	5,917	2,650
Losses (gains) from investments in securities	5,445	(2,969)
Non-cash portion of interest expense	5,646	5,447
(Gains) losses on sales of real estate	(410,165)	905
Change in assets and liabilities:
Tenant and other receivables, net	17,784	(14,000)
Note receivable, net	(128)	(125)
Accrued rental income, net	(27,285)	(15,570)
Prepaid expenses and other assets	(93,819)	(68,554)
Lease liabilities - operating leases	393	370
Accounts payable and accrued expenses	(48,591)	258
Accrued interest payable	(7,644)	(160)
Other liabilities	(21,296)	(17,831)
Tenant leasing costs	(17,777)	(18,420)
Total adjustments	(401,949)	76,075
Net cash provided by operating activities	175,197	207,234
Cash flows from investing activities:
Acquisition of real estate	0	(43,061)
Construction in progress	(143,160)	(85,632)
Building and other capital improvements	(39,154)	(32,719)
Tenant improvements	(64,172)	(54,242)
Proceeds from sales of real estate	259,489	20,019
Capital contributions to unconsolidated joint ventures	(89,997)	(26,995)
Investments in securities, net	3,201	(885)
Net cash used in investing activities	(73,793)	(223,515)
Cash flows from financing activities:
Repayments of mortgage notes payable	(4,212)	(5,645)
Borrowings on unsecured line of credit	265,000	50,000
Repayments of unsecured line of credit	(15,000)	(50,000)
Payments on finance lease obligations	0	(470)
Deferred financing costs	(11)	(186)
Net proceeds from equity transactions	3,349	1,792
Dividends and distributions	(171,964)	(166,362)
Contributions from noncontrolling interests in property partnerships	3,876	4,387
Distributions to noncontrolling interests in property partnerships	(15,750)	(24,128)
Net cash provided by (used in) financing activities	65,288	(190,612)
Net increase (decrease) in cash and cash equivalents and cash held in escrows	166,692	(206,893)
Cash and cash equivalents and cash held in escrows, beginning of year	691,886	639,191
Cash and cash equivalents and cash held in escrows, end of year	858,578	432,298
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period	644,950	543,359
Cash held in escrows, beginning of period	46,936	95,832
Cash and cash equivalents, end of period	660,733	360,091
Cash held in escrows,end of period	197,845	72,207
Supplemental disclosures:
Cash paid for interest	114,696	107,094
Interest capitalized	14,149	11,813
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(38,782)	(31,640)
Change in real estate included in accounts payable and accrued expenses	(27,415)	49,689
Real estate acquired through capital leases	0	122,563
Accrued rental income, net deconsolidated	(4,558)	0
Tenant leasing costs, net deconsolidated	(3,462)	0
Building and other capital improvements, net deconsolidated	(111,889)	0
Tenant improvements, net deconsolidated	(12,331)	0
Investment in unconsolidated joint venture recorded upon deconsolidation	347,898	0
Dividends and distributions declared but not paid	171,026	165,352
Conversions of noncontrolling interests to stockholders’ equity	15,495	492
Issuance of restricted securities to employees and directors	43,104	37,428
Boston Properties Limited Partnership
Net income	588,444	134,837
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	169,285	162,682
Amortization of right of use assets - operating leases	583	605
Impairment loss	0	22,272
Non-cash compensation expense	17,525	15,050
Loss (income) from unconsolidated joint ventures	369	(213)
Distributions of net cash flow from operations of unconsolidated joint ventures	5,917	2,650
Losses (gains) from investments in securities	5,445	(2,969)
Non-cash portion of interest expense	5,646	5,447
(Gains) losses on sales of real estate	(419,654)	905
Change in assets and liabilities:
Tenant and other receivables, net	17,784	(14,000)
Note receivable, net	(128)	(125)
Accrued rental income, net	(27,285)	(15,570)
Prepaid expenses and other assets	(93,819)	(68,554)
Lease liabilities - operating leases	393	370
Accounts payable and accrued expenses	(48,591)	258
Accrued interest payable	(7,644)	(160)
Other liabilities	(21,296)	(17,831)
Tenant leasing costs	(17,777)	(18,420)
Total adjustments	(413,247)	72,397
Net cash provided by operating activities	175,197	207,234
Cash flows from investing activities:
Acquisition of real estate	0	(43,061)
Construction in progress	(143,160)	(85,632)
Building and other capital improvements	(39,154)	(32,719)
Tenant improvements	(64,172)	(54,242)
Proceeds from sales of real estate	259,489	20,019
Capital contributions to unconsolidated joint ventures	(89,997)	(26,995)
Investments in securities, net	3,201	(885)
Net cash used in investing activities	(73,793)	(223,515)
Cash flows from financing activities:
Repayments of mortgage notes payable	(4,212)	(5,645)
Borrowings on unsecured line of credit	265,000	50,000
Repayments of unsecured line of credit	(15,000)	(50,000)
Payments on finance lease obligations	0	(470)
Deferred financing costs	(11)	(186)
Net proceeds from equity transactions	3,349	1,792
Dividends and distributions	(171,964)	(166,362)
Contributions from noncontrolling interests in property partnerships	3,876	4,387
Distributions to noncontrolling interests in property partnerships	(15,750)	(24,128)
Net cash provided by (used in) financing activities	65,288	(190,612)
Net increase (decrease) in cash and cash equivalents and cash held in escrows	166,692	(206,893)
Cash and cash equivalents and cash held in escrows, beginning of year	691,886	639,191
Cash and cash equivalents and cash held in escrows, end of year	858,578	432,298
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period	644,950	543,359
Cash held in escrows, beginning of period	46,936	95,832
Cash and cash equivalents, end of period	660,733	360,091
Cash held in escrows,end of period	197,845	72,207
Supplemental disclosures:
Cash paid for interest	114,696	107,094
Interest capitalized	14,149	11,813
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(38,782)	(31,640)
Change in real estate included in accounts payable and accrued expenses	(27,415)	49,689
Real estate acquired through capital leases	0	122,563
Accrued rental income, net deconsolidated	(4,558)	0
Tenant leasing costs, net deconsolidated	(3,462)	0
Building and other capital improvements, net deconsolidated	(111,889)	0
Tenant improvements, net deconsolidated	(12,331)	0
Investment in unconsolidated joint venture recorded upon deconsolidation	347,898	0
Dividends and distributions declared but not paid	171,026	165,352
Conversions of noncontrolling interests to stockholders’ equity	15,495	492
Issuance Of Restricted Units To Employees And Directors	$ 43,104	$ 37,428