Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,615,237 and $6,592,019 at March 31, 2021 and December 31, 2020, respectively)	$ 23,156,924	$ 22,969,110
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2021 and December 31, 2020, respectively)	237,017	237,393
Right of use assets - operating leases	144,143	146,406
Less: accumulated depreciation (amounts related to VIEs of $(1,188,554) and $(1,158,548) at March 31, 2021 and December 31, 2020, respectively)	(5,665,061)	(5,534,102)
Total real estate	17,873,023	17,818,807
Cash and cash equivalents (amounts related to VIEs of $289,737 and $340,642 at March 31, 2021 and December 31, 2020, respectively)	697,369	1,668,742
Cash held in escrows	251,814	50,587
Investments in securities	39,002	39,457
Tenant and other receivables, net (amounts related to VIEs of $5,846 and $10,911 at March 31, 2021 and December 31, 2020, respectively)	51,271	77,411
Related party note receivable, net	77,640	77,552
Notes receivable, net	18,891	18,729
Accrued rental income, net (amounts related to VIEs of $341,772 and $336,594 at March 31, 2021 and December 31, 2020, respectively)	1,145,066	1,122,502
Deferred charges, net (amounts related to VIEs of $177,647 and $183,306 at March 31, 2021 and December 31, 2020, respectively)	622,649	640,085
Prepaid expenses and other assets (amounts related to VIEs of $45,075 and $13,137 at March 31, 2021 and December 31, 2020, respectively)	129,102	33,840
Investments in unconsolidated joint ventures	1,307,725	1,310,478
Total assets	22,213,552	22,858,190
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $2,904,672 and $2,907,590 at March 31, 2021 and December 31, 2020, respectively)	2,904,672	2,909,081
Unsecured senior notes, net	9,631,592	9,639,287
Unsecured line of credit	0	0
Unsecured term loan, net	0	499,390
Lease liabilities - finance leases (amounts related to VIEs of $20,345 and $20,306 at March 31, 2021 and December 31, 2020, respectively)	239,361	236,492
Lease liabilities - operating leases	200,383	201,713
Accounts payable and accrued expenses (amounts related to VIEs of $15,957 and $23,128 at March 31, 2021 and December 31, 2020, respectively)	260,875	336,264
Dividends and distributions payable	171,003	171,082
Accrued interest payable	76,675	106,288
Preferred stock redemption liability	200,000	0
Other liabilities (amounts related to VIEs of $141,547 and $158,805 at March 31, 2021 and December 31, 2020, respectively)	399,965	412,084
Total liabilities	14,084,526	14,511,681
Redeemable deferred stock units— 75,834 and 72,966 units outstanding at redemption value at March 31, 2021 and December 31, 2020, respectively	7,679	6,897
Equity / Capital:
Excess stock, $0.01 par value, 150,000,000 shares authorized, none issued or outstanding	0	0
Preferred stock, $0.01 par value, 50,000,000 shares authorized;
5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2020	0	200,000
Common stock, $0.01 par value, 250,000,000 shares authorized, 156,153,100 and 155,797,725 issued and 156,074,200 and 155,718,825 outstanding at March 31, 2021 and December 31, 2020, respectively	1,561	1,557
Additional paid-in capital	6,392,923	6,356,791
Dividends in excess of earnings	(570,982)	(509,653)
Treasury common stock at cost, 78,900 shares at March 31, 2021 and December 31, 2020	(2,722)	(2,722)
Accumulated other comprehensive loss	(45,139)	(49,890)
Total stockholders' equity attributable to Boston Properties, Inc.	5,775,641	5,996,083
Noncontrolling interests:
Common units of the Operating Partnership	620,106	616,596
Property partnerships	1,725,600	1,726,933
Total equity / capital	8,121,347	8,339,612
Total liabilities and equity / capital	22,213,552	22,858,190
Boston Properties Limited Partnership
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,615,237 and $6,592,019 at March 31, 2021 and December 31, 2020, respectively)	22,781,429	22,592,301
Right of use assets - finance leases (amounts related to VIEs of $21,000 and $21,000 at March 31, 2021 and December 31, 2020, respectively)	237,017	237,393
Right of use assets - operating leases	144,143	146,406
Less: accumulated depreciation (amounts related to VIEs of $(1,188,554) and $(1,158,548) at March 31, 2021 and December 31, 2020, respectively)	(5,557,784)	(5,428,576)
Total real estate	17,604,805	17,547,524
Cash and cash equivalents (amounts related to VIEs of $289,737 and $340,642 at March 31, 2021 and December 31, 2020, respectively)	697,369	1,668,742
Cash held in escrows	251,814	50,587
Investments in securities	39,002	39,457
Tenant and other receivables, net (amounts related to VIEs of $5,846 and $10,911 at March 31, 2021 and December 31, 2020, respectively)	51,271	77,411
Related party note receivable, net	77,640	77,552
Notes receivable, net	18,891	18,729
Accrued rental income, net (amounts related to VIEs of $341,772 and $336,594 at March 31, 2021 and December 31, 2020, respectively)	1,145,066	1,122,502
Deferred charges, net (amounts related to VIEs of $177,647 and $183,306 at March 31, 2021 and December 31, 2020, respectively)	622,649	640,085
Prepaid expenses and other assets (amounts related to VIEs of $45,075 and $13,137 at March 31, 2021 and December 31, 2020, respectively)	129,102	33,840
Investments in unconsolidated joint ventures	1,307,725	1,310,478
Total assets	21,945,334	22,586,907
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $2,904,672 and $2,907,590 at March 31, 2021 and December 31, 2020, respectively)	2,904,672	2,909,081
Unsecured senior notes, net	9,631,592	9,639,287
Unsecured line of credit	0	0
Unsecured term loan, net	0	499,390
Lease liabilities - finance leases (amounts related to VIEs of $20,345 and $20,306 at March 31, 2021 and December 31, 2020, respectively)	239,361	236,492
Lease liabilities - operating leases	200,383	201,713
Accounts payable and accrued expenses (amounts related to VIEs of $15,957 and $23,128 at March 31, 2021 and December 31, 2020, respectively)	260,875	336,264
Dividends and distributions payable	171,003	171,082
Accrued interest payable	76,675	106,288
Preferred stock redemption liability	200,000	0
Other liabilities (amounts related to VIEs of $141,547 and $158,805 at March 31, 2021 and December 31, 2020, respectively)	399,965	412,084
Total liabilities	14,084,526	14,511,681
Redeemable deferred stock units— 75,834 and 72,966 units outstanding at redemption value at March 31, 2021 and December 31, 2020, respectively	7,679	6,897
Redeemable partnership units— 16,053,640 and 16,037,121 common units and 1,525,306 and 1,336,115 long term incentive units outstanding at redemption value at March 31, 2021 and December 31, 2020, respectively	1,780,044	1,643,024
Preferred stock, $0.01 par value, 50,000,000 shares authorized;
5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2020	0	193,623
Boston Properties Limited Partnership partners’ capital— 1,736,531 and 1,730,921 general partner units and 154,337,669 and 153,987,904 limited partner units outstanding at March 31, 2021 and December 31, 2020, respectively	4,392,624	4,554,639
Accumulated other comprehensive loss	(45,139)	(49,890)
Total partners’ capital	4,347,485	4,698,372
Noncontrolling interests in property partnerships	1,725,600	1,726,933
Noncontrolling interests:
Total equity / capital	6,073,085	6,425,305
Total liabilities and equity / capital	$ 21,945,334	$ 22,586,907