Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 216,312	$ 115,564
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	165,797	159,205
Non-cash compensation expense	14,772	10,802
Income from unconsolidated joint ventures	(461)	(3,084)
Distributions of net cash flow from operations of unconsolidated joint ventures	847	1,861
Losses (gains) from investments in securities	126	(1,042)
Non-cash portion of interest expense	5,299	(7,729)
Gains on sales of real estate	(96,397)	(133)
Change in assets and liabilities:
Tenant and other receivables, net	22,790	19,023
Accrued rental income, net	(26,319)	(9,158)
Prepaid expenses and other assets	(66,968)	(21,197)
Accounts payable and accrued expenses	(13,913)	(16,306)
Accrued interest payable	12,399	22,781
Other liabilities	23,089	(7,104)
Tenant leasing costs	(31,595)	(23,631)
Total adjustments	9,466	124,288
Net cash provided by operating activities	225,778	239,852
Cash flows from investing activities:
Construction in progress	(150,060)	(154,518)
Building and other capital improvements	(53,550)	(43,687)
Tenant improvements	(47,157)	(50,810)
Proceeds from sales of real estate	116,120	133
Capital contributions to unconsolidated joint ventures	(48,823)	(17,980)
Investments in securities, net	(318)	(961)
Net cash used in investing activities	(183,788)	(267,823)
Cash flows from financing activities:
Repayments of mortgage notes payable	(5,333)	(5,038)
Borrowings on unsecured line of credit	260,000	175,000
Repayments of unsecured line of credit	(190,000)	(70,000)
Payments on capital lease obligations	(3)	(22)
Payments on real estate financing transactions	(444)	(480)
Deferred financing costs	(16)	0
Net proceeds from equity transactions	(723)	(183)
Dividends and distributions	(140,288)	(131,555)
Contributions from noncontrolling interests in property partnerships	15,267	8,145
Distributions to noncontrolling interests in property partnerships	(30,690)	(13,801)
Net cash used in financing activities	(92,230)	(37,934)
Net decrease in cash and cash equivalents and cash held in escrows	(50,240)	(65,905)
Cash and cash equivalents and cash held in escrows, beginning of period	505,369	420,088
Cash and cash equivalents and cash held in escrows, end of period	455,129	354,183
Reconciliation of cash and cash equivalents and cash held in escrows:
Cash and cash equivalents, beginning of period	434,767	356,914
Cash held in escrows, beginning of period	70,602	63,174
Cash and Cash Equivalents, end of period	294,571	302,939
Cash held in escrows, end of period	160,558	51,244
Supplemental disclosures:
Cash paid for interest	89,412	92,774
Interest capitalized	17,378	12,345
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(29,609)	(49,292)
Additions to real estate included in accounts payable and accrued expenses	35,245	44,708
Dividends and distributions declared but not paid	139,218	130,418
Conversions of noncontrolling interests to stockholders’ equity	832	793
Issuance of restricted securities to employees	36,433	34,592
Boston Properties Limited Partnership
Cash flows from operating activities:
Net income	220,766	117,711
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	163,853	157,058
Non-cash compensation expense	14,772	10,802
Income from unconsolidated joint ventures	(461)	(3,084)
Distributions of net cash flow from operations of unconsolidated joint ventures	847	1,861
Losses (gains) from investments in securities	126	(1,042)
Non-cash portion of interest expense	5,299	(7,729)
Gains on sales of real estate	(98,907)	(133)
Change in assets and liabilities:
Tenant and other receivables, net	22,790	19,023
Accrued rental income, net	(26,319)	(9,158)
Prepaid expenses and other assets	(66,968)	(21,197)
Accounts payable and accrued expenses	(13,913)	(16,306)
Accrued interest payable	12,399	22,781
Other liabilities	23,089	(7,104)
Tenant leasing costs	(31,595)	(23,631)
Total adjustments	5,012	122,141
Net cash provided by operating activities	225,778	239,852
Cash flows from investing activities:
Construction in progress	(150,060)	(154,518)
Building and other capital improvements	(53,550)	(43,687)
Tenant improvements	(47,157)	(50,810)
Proceeds from sales of real estate	116,120	133
Capital contributions to unconsolidated joint ventures	(48,823)	(17,980)
Investments in securities, net	(318)	(961)
Net cash used in investing activities	(183,788)	(267,823)
Cash flows from financing activities:
Repayments of mortgage notes payable	(5,333)	(5,038)
Borrowings on unsecured line of credit	260,000	175,000
Repayments of unsecured line of credit	(190,000)	(70,000)
Payments on capital lease obligations	(3)	(22)
Payments on real estate financing transactions	(444)	(480)
Deferred financing costs	(16)	0
Net proceeds from equity transactions	(723)	(183)
Dividends and distributions	(140,288)	(131,555)
Contributions from noncontrolling interests in property partnerships	15,267	8,145
Distributions to noncontrolling interests in property partnerships	(30,690)	(13,801)
Net cash used in financing activities	(92,230)	(37,934)
Net decrease in cash and cash equivalents and cash held in escrows	(50,240)	(65,905)
Cash and cash equivalents and cash held in escrows, beginning of period	505,369	420,088
Cash and cash equivalents and cash held in escrows, end of period	455,129	354,183
Reconciliation of cash and cash equivalents and cash held in escrows:
Cash and cash equivalents, beginning of period	434,767	356,914
Cash held in escrows, beginning of period	70,602	63,174
Cash and Cash Equivalents, end of period	294,571	302,939
Cash held in escrows, end of period	160,558	51,244
Supplemental disclosures:
Cash paid for interest	89,412	92,774
Interest capitalized	17,378	12,345
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(29,609)	(49,292)
Additions to real estate included in accounts payable and accrued expenses	35,245	44,708
Dividends and distributions declared but not paid	139,218	130,418
Conversions of noncontrolling interests to stockholders’ equity	832	793
Issuance of restricted securities to employees	$ 36,433	$ 34,592