Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 430,278	$ 405,083
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	463,288	516,371
Impairment loss	0	1,783
Non-cash compensation expense	27,260	25,290
Income from unconsolidated joint ventures	(7,035)	(5,489)
Distributions of net cash flow from operations of unconsolidated joint ventures	8,563	11,645
Gains from investments in securities	(2,716)	(1,713)
(Gains) losses from early extinguishments of debt	(14,444)	371
Non-cash portion of interest expense	(6,667)	(27,386)
Gains on sales of real estate	(6,791)	(80,606)
Change in assets and liabilities:
Cash held in escrows	7,795	1,675
Tenant and other receivables, net	12,528	22,135
Accrued rental income, net	(36,012)	(14,618)
Prepaid expenses and other assets	(13,633)	4,883
Accounts payable and accrued expenses	7,861	16,852
Accrued interest payable	(144,833)	44,242
Other liabilities	(65,031)	(114,321)
Tenant leasing costs	(67,699)	(62,412)
Total adjustments	162,434	338,702
Net cash provided by operating activities	592,712	743,785
Cash flows from investing activities:
Acquisitions of real estate	(15,953)	(78,000)
Construction in progress	(452,283)	(359,716)
Building and other capital improvements	(162,395)	(81,842)
Tenant improvements	(152,749)	(167,762)
Proceeds from sales of real estate	29,810	122,750
Proceeds from sales of real estate placed in escrow	(29,810)	(122,647)
Proceeds from sales of real estate released from escrow	16,640	122,647
Cash released from escrow for investing activities	9,638	6,694
Cash released from escrow for land sale contracts	0	1,403
Cash placed in escrow for investment in unconsolidated joint venture	(25,000)	0
Capital contributions to unconsolidated joint ventures	(89,874)	(546,982)
Capital distributions from unconsolidated joint ventures	251,000	0
Investments in securities, net	(1,451)	(929)
Net cash used in investing activities	(622,427)	(1,104,384)
Cash flows from financing activities:
Proceeds from mortgage notes payable	2,300,000	0
Repayments of mortgage notes payable	(1,313,890)	(1,323,284)
Proceeds from unsecured senior notes	0	1,989,790
Borrowings on unsecured line of credit	470,000	0
Repayments of unsecured line of credit	(470,000)	0
Repayments of mezzanine notes payable	(306,000)	0
Repayments of outside members’ notes payable	(70,424)	0
Payments on capital lease obligations	(373)	0
Payments on real estate financing transactions	(1,306)	(4,712)
Deposit on mortgage note payable interest rate lock	(23,200)	0
Return of deposit on mortgage note payable interest rate lock	23,200	0
Deferred financing costs	(44,083)	(16,101)
Net proceeds from equity transactions	241	(270)
Dividends and distributions	(394,900)	(557,262)
Contributions from noncontrolling interests in property partnerships	38,196	6,737
Distributions to noncontrolling interests in property partnerships	(41,605)	(38,694)
Net cash provided by financing activities	165,856	56,204
Net increase (decrease) in cash and cash equivalents	136,141	(304,395)
Cash and cash equivalents, beginning of period	356,914	723,718
Cash and cash equivalents, end of period	493,055	419,323
Supplemental disclosures:
Cash paid for interest	477,189	327,053
Interest capitalized	43,286	28,956
Non-cash investing and financing activities:
Write off of fully depreciated real estate	(103,972)	(168,861)
Additions to real estate included in accounts payable and accrued expenses	36,609	11,864
Real estate acquired through capital lease	28,962	0
Outside members’ notes payable contributed to noncontrolling interests in property partnerships	109,576	0
Dividends and distributions declared but not paid	130,434	113,038
Conversions of noncontrolling interests to stockholders’ equity	16,812	5,881
Issuance of restricted securities to employees	35,711	33,711
Boston Properties Limited Partnership
Cash flows from operating activities:
Net income	437,041	416,389
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	457,102	507,234
Impairment loss	0	1,783
Non-cash compensation expense	27,260	25,290
Income from unconsolidated joint ventures	(7,035)	(5,489)
Distributions of net cash flow from operations of unconsolidated joint ventures	8,563	11,645
Gains from investments in securities	(2,716)	(1,713)
(Gains) losses from early extinguishments of debt	(14,444)	371
Non-cash portion of interest expense	(6,667)	(27,386)
Gains on sales of real estate	(7,368)	(82,775)
Change in assets and liabilities:
Cash held in escrows	7,795	1,675
Tenant and other receivables, net	12,528	22,135
Accrued rental income, net	(36,012)	(14,618)
Prepaid expenses and other assets	(13,633)	4,883
Accounts payable and accrued expenses	7,861	16,852
Accrued interest payable	(144,833)	44,242
Other liabilities	(65,031)	(114,321)
Tenant leasing costs	(67,699)	(62,412)
Total adjustments	155,671	327,396
Net cash provided by operating activities	592,712	743,785
Cash flows from investing activities:
Acquisitions of real estate	(15,953)	(78,000)
Construction in progress	(452,283)	(359,716)
Building and other capital improvements	(162,395)	(81,842)
Tenant improvements	(152,749)	(167,762)
Proceeds from sales of real estate	29,810	122,750
Proceeds from sales of real estate placed in escrow	(29,810)	(122,647)
Proceeds from sales of real estate released from escrow	16,640	122,647
Cash released from escrow for investing activities	9,638	6,694
Cash released from escrow for land sale contracts	0	1,403
Cash placed in escrow for investment in unconsolidated joint venture	(25,000)	0
Capital contributions to unconsolidated joint ventures	(89,874)	(546,982)
Capital distributions from unconsolidated joint ventures	251,000	0
Investments in securities, net	(1,451)	(929)
Net cash used in investing activities	(622,427)	(1,104,384)
Cash flows from financing activities:
Proceeds from mortgage notes payable	2,300,000	0
Repayments of mortgage notes payable	(1,313,890)	(1,323,284)
Proceeds from unsecured senior notes	0	1,989,790
Borrowings on unsecured line of credit	470,000	0
Repayments of unsecured line of credit	(470,000)	0
Repayments of mezzanine notes payable	(306,000)	0
Repayments of outside members’ notes payable	(70,424)	0
Payments on capital lease obligations	(373)	0
Payments on real estate financing transactions	(1,306)	(4,712)
Deposit on mortgage note payable interest rate lock	(23,200)	0
Return of deposit on mortgage note payable interest rate lock	23,200	0
Deferred financing costs	(44,083)	(16,101)
Net proceeds from equity transactions	241	(270)
Dividends and distributions	(394,900)	(557,262)
Contributions from noncontrolling interests in property partnerships	38,196	6,737
Distributions to noncontrolling interests in property partnerships	(41,605)	(38,694)
Net cash provided by financing activities	165,856	56,204
Net increase (decrease) in cash and cash equivalents	136,141	(304,395)
Cash and cash equivalents, beginning of period	356,914	723,718
Cash and cash equivalents, end of period	493,055	419,323
Supplemental disclosures:
Cash paid for interest	477,189	327,053
Interest capitalized	43,286	28,956
Non-cash investing and financing activities:
Write off of fully depreciated real estate	(102,795)	(164,528)
Additions to real estate included in accounts payable and accrued expenses	36,609	11,864
Real estate acquired through capital lease	28,962	0
Outside members’ notes payable contributed to noncontrolling interests in property partnerships	109,576	0
Dividends and distributions declared but not paid	130,434	113,038
Conversions of noncontrolling interests to stockholders’ equity	16,812	5,881
Issuance of restricted securities to employees	$ 35,711	$ 33,711