Consolidated Statements Of Cash Flows $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)
Net income	$ 176,957	$ 128,147
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	177,624	176,565
Amortization of right of use assets - operating leases	529	2,263
Non-cash compensation expense	21,235	20,090
Loss (income) from unconsolidated joint ventures	(2,189)	(5,225)
Distributions of net cash flow from operations of unconsolidated joint ventures	6,385	3,972
Losses (gains) from investments in securities	2,262	(1,659)
Allowance for current expected credit losses	(234)	(128)
Non-cash portion of interest expense	5,960	5,984
Settlement of accreted debt discount on redemption of unsecured senior notes	0	(6,290)
Loss from early extinguishment of debt	0	898
Gains on sales of real estate	(22,701)	0
Change in assets and liabilities:
Tenant and other receivables, net	17,635	26,020
Notes receivable, net	(8)	(140)
Accrued rental income, net	(29,567)	(9,413)
Prepaid expenses and other assets	(71,731)	(96,351)
Lease liabilities - operating leases	116	(1,330)
Accounts payable and accrued expenses	(31,800)	(21,578)
Accrued interest payable	(3,933)	(28,970)
Other liabilities	(12,146)	(24,177)
Tenant leasing costs	(14,904)	(16,615)
Total adjustments	42,533	23,916
Net cash provided by operating activities	219,490	152,063
Cash flows from investing activities:
Acquisitions of real estate	(3,580)	0
Construction in progress	(100,313)	(119,496)
Building and other capital improvements	(26,811)	(32,717)
Tenant improvements	(55,168)	(93,201)
Proceeds from sales of real estate	35,397	0
Capital contributions to unconsolidated joint ventures	(26,293)	(16,684)
Capital distributions from unconsolidated joint ventures	20,095	122
Proceeds from sale of investment in unconsolidated joint venture	0	17,589
Investments in securities, net	5,338	2,114
Net cash used in investing activities	(151,335)	(242,273)
Cash flows from financing activities:
Repayments of mortgage notes payable	0	(5,374)
Proceeds from unsecured senior notes	0	846,345
Redemption of unsecured senior notes	0	(843,710)
Borrowings on unsecured line of credit	190,000	0
Repayments of unsecured line of credit	(80,000)	0
Repayment of unsecured term loan	0	500,000
Payments on finance lease obligations	0	0
Deferred financing costs	(359)	(7,145)
Debt prepayment and extinguishment costs	0	(185)
Net proceeds from equity transactions	(332)	19,643
Dividends and distributions	(170,488)	(171,566)
Contributions from noncontrolling interests in property partnerships	849	281
Distributions to noncontrolling interests in property partnerships	(26,640)	(18,225)
Net cash used in financing activities	(86,970)	(679,936)
Net increase (decrease) in cash and cash equivalents and cash held in escrows	(18,815)	(770,146)
Cash and cash equivalents and cash held in escrows, beginning of period	501,158	1,719,329
Cash and cash equivalents and cash held in escrows, end of period	482,343	949,183
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period	452,692	1,668,742
Cash held in escrows, beginning of period	48,466	50,587
Cash and cash equivalents, end of period	436,271	697,369
Cash held in escrows,end of period	46,072	251,814
Supplemental disclosures:
Cash paid for interest	111,904	146,781
Interest capitalized	13,740	12,032
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(34,946)	(25,161)
Change in real estate included in accounts payable and accrued expenses	16,907	(42,778)
Preferred stock redemption liability	0	200,000
Deferred distributions from sale of investment in unconsolidated joint venture	0	5,808
Deferred proceeds from sale of investment in unconsolidated joint venture	0	200
Dividends and distributions declared but not paid	170,869	171,003
Conversions of noncontrolling interests to stockholders’ equity	5,028	4,198
Issuance of restricted securities to employees and non-employee directors	46,082	41,255
Boston Properties Limited Partnership
Net income	179,378	131,212
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	175,886	173,500
Amortization of right of use assets - operating leases	529	2,263
Non-cash compensation expense	21,235	20,090
Loss (income) from unconsolidated joint ventures	(2,189)	(5,225)
Distributions of net cash flow from operations of unconsolidated joint ventures	6,385	3,972
Losses (gains) from investments in securities	2,262	(1,659)
Allowance for current expected credit losses	(234)	(128)
Non-cash portion of interest expense	5,960	5,984
Settlement of accreted debt discount on redemption of unsecured senior notes	0	(6,290)
Loss from early extinguishment of debt	0	898
Gains on sales of real estate	(23,384)	0
Change in assets and liabilities:
Tenant and other receivables, net	17,635	26,020
Notes receivable, net	(8)	(140)
Accrued rental income, net	(29,567)	(9,413)
Prepaid expenses and other assets	(71,731)	(96,351)
Lease liabilities - operating leases	116	(1,330)
Accounts payable and accrued expenses	(31,800)	(21,578)
Accrued interest payable	(3,933)	(28,970)
Other liabilities	(12,146)	(24,177)
Tenant leasing costs	(14,904)	(16,615)
Total adjustments	40,112	20,851
Net cash provided by operating activities	219,490	152,063
Cash flows from investing activities:
Acquisitions of real estate	(3,580)	0
Construction in progress	(100,313)	(119,496)
Building and other capital improvements	(26,811)	(32,717)
Tenant improvements	(55,168)	(93,201)
Proceeds from sales of real estate	35,397	0
Capital contributions to unconsolidated joint ventures	(26,293)	(16,684)
Capital distributions from unconsolidated joint ventures	20,095	122
Proceeds from sale of investment in unconsolidated joint venture	0	17,589
Investments in securities, net	5,338	2,114
Net cash used in investing activities	(151,335)	(242,273)
Cash flows from financing activities:
Repayments of mortgage notes payable	0	(5,374)
Proceeds from unsecured senior notes	0	846,345
Redemption of unsecured senior notes	0	(843,710)
Borrowings on unsecured line of credit	190,000	0
Repayments of unsecured line of credit	(80,000)	0
Repayment of unsecured term loan	0	(500,000)
Payments on finance lease obligations	0	0
Deferred financing costs	(359)	(7,145)
Debt prepayment and extinguishment costs	0	(185)
Net proceeds from equity transactions	(332)	19,643
Dividends and distributions	(170,488)	(171,566)
Contributions from noncontrolling interests in property partnerships	849	281
Distributions to noncontrolling interests in property partnerships	(26,640)	(18,225)
Net cash used in financing activities	(86,970)	(679,936)
Net increase (decrease) in cash and cash equivalents and cash held in escrows	(18,815)	(770,146)
Cash and cash equivalents and cash held in escrows, beginning of period	501,158	1,719,329
Cash and cash equivalents and cash held in escrows, end of period	482,343	949,183
Reconciliation of cash and cash equivalents and cash held in escrow
Cash and cash equivalents, beginning of period	452,692	1,668,742
Cash held in escrows, beginning of period	48,466	50,587
Cash and cash equivalents, end of period	436,271	697,369
Cash held in escrows,end of period	46,072	251,814
Supplemental disclosures:
Cash paid for interest	111,904	146,781
Interest capitalized	13,740	12,032
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(34,946)	(23,847)
Change in real estate included in accounts payable and accrued expenses	16,907	(42,778)
Preferred stock redemption liability	0	200,000
Deferred distributions from sale of investment in unconsolidated joint venture	0	5,808
Deferred proceeds from sale of investment in unconsolidated joint venture	0	200
Dividends and distributions declared but not paid	170,869	171,003
Conversions of noncontrolling interests to stockholders’ equity	5,028	4,198
Issuance of restricted securities to employees and non-employee directors	$ 46,082	$ 41,255