Real estate acquisitions and amortization of intangibles (Details) - USD ($)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Amortization of Deferred Charges [Abstract]
Amortization of Debt Issuance Costs		$ 1,943,000	$ 1,357,000	$ 1,296,000
Amortization of facility fees		1,005,000	713,000	751,000
Amortization of deferred leasing costs		22,133,000	18,950,000	16,209,000
Amortization of above and below Market Leases		(2,483,000)	(2,565,000)	(1,048,000)
Amortization of Acquired-in-place lease intangibles		7,942,000	9,489,000	5,980,000
Projected amortization of acquired-in-place lease intangibles [Abstract]
Future Amortization In Place Lease Expense Year One		6,611,000
Future Amortization In Place Lease Expense Year Two		5,421,000
Future Amortization In Place Lease Expense Year Three		3,656,000
Future Amortization In Place Lease Expense Year Four		1,837,000
Future Amortization In Place Lease Expense Year Five		887,000
Future Amortization In Place Lease Expense After Year Five		1,793,000
Total acquired in-place lease intangibles, net of accumulated amortization		20,205,000	20,905,000
Asset Acquisition [Abstract]
Land		814,364,000	730,445,000
Buildings and building improvements		3,336,615,000	3,012,319,000
Tenant and other improvements		684,573,000	633,817,000
Right of use assets - Ground leases (operating)	[1]	17,996,000	19,391,000
In-place lease intangibles		39,600,000	37,181,000
Below market lease intangibles		(11,451,000)	(10,735,000)
Commercial Real Estate
Asset Acquisition [Abstract]
Land		44,676,000	127,402,000	42,554,000
Buildings and building improvements		111,082,000	335,335,000	225,645,000
Tenant and other improvements		4,346,000	11,502,000	4,907,000
Right of use assets - Ground leases (operating)		0	0	12,708,000
Total real estate properties acquired		160,104,000	474,239,000	285,814,000
In-place lease intangibles	[2]	7,242,000	11,871,000	9,949,000
Above market lease intangibles	[2]	0	0	6,000
Below market lease intangibles	[3]	(2,230,000)	(4,059,000)	(3,836,000)
Operating lease liabilities - Ground leases	[4]	0	0	12,708,000
Total assets acquired, net of liabilities assumed		$ 165,116,000	$ 482,051,000	$ 279,225,000
Weighted Average Remaining Lease Term of Acquired Properties		8 years	3 years 10 months 24 days	2 years 10 months 24 days

[1] See Ground Leases discussion below for information regarding the Company’s right of use assets for ground leases.

[2] In-place lease intangibles and above market lease intangibles are each included in Other assets on the Consolidated Balance Sheets. These costs are amortized over the remaining terms of the associated leases in place at the time of acquisition.

[3] Below market lease intangibles are included in Other liabilities on the Consolidated Balance Sheets. These costs are amortized over the remaining terms of the associated leases in place at the time of acquisition.

[4] Operating lease liabilities — Ground leases are included in Other liabilities on the Consolidated Balance Sheets.