Debt And Lines Of Credit , Narrative - Collateralized Term Loans (Details)		1 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 28, 2021 USD ($)	Oct. 31, 2019 USD ($)	Jun. 30, 2021 USD ($) site loans properties Rate	Jun. 30, 2020 USD ($) loans Rate	Mar. 31, 2020 USD ($)	Jun. 30, 2021 USD ($) site loans properties Rate	Jun. 30, 2020 USD ($) loans Rate	Dec. 31, 2020 USD ($) site Rate	Jun. 14, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 22, 2020 USD ($)	Apr. 25, 2017 USD ($)
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt			$ 8,108,000	$ 1,930,000		$ 8,108,000	$ 5,209,000
Weighted average interest rate | Rate			3.519%			3.519%		3.37%
Sites, Wet Slips and Dry Storage Spaces | site			4,469			4,469		45,800
Debt weighted average to maturity, length						10 years 4 months 24 days		9 years 4 months 24 days
Total debt			$ 3,457,734,000			$ 3,457,734,000		$ 3,489,983,000
Document Period End Date			Jun. 30, 2021
Long-term Debt			$ 201,900,000			201,900,000				$ 6,500,000
Line of credit and other								1,197,181,000
Unsecured Debt			853,441,000			853,441,000		1,267,093,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt			190,300,000			190,300,000		40,400,000
Line of credit and other			$ 191,841,000			191,841,000
Safe Harbor | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt						$ (7,900,000)
Line of credit, borrowing capacity											$ 1,800,000,000
Collateralized Term Loan 1
Debt Instrument [Line Items]
Number Of Collateralized Term Loans | loans			4	3		4	3
Collateralized Term Loan 2
Debt Instrument [Line Items]
Number Of Collateralized Term Loans | loans			2	1		2	1
Collateralized Term Loan 3
Debt Instrument [Line Items]
Number Of Collateralized Term Loans | loans			1	2		1	2
A&R Facility [Member] | Safe Harbor | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt						$ (200,000)
Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount					$ 230,000,000			$ 268,800,000
Debt instrument term					15 years			12 years
Debt Instrument, Interest Rate, Stated Percentage					2.995%			2.662%
Total debt			$ 3,400,000,000			3,400,000,000
Long-term Debt								$ 0
Secured Debt [Member] | Collateralized Term Loan 1
Debt Instrument [Line Items]
Debt instrument, face amount								8,800,000
Secured Debt [Member] | Collateralized Term Loan 2
Debt Instrument [Line Items]
Debt instrument, face amount								39,500,000
Secured Debt [Member] | Collateralized Term Loan 3
Debt Instrument [Line Items]
Debt instrument, face amount								220,500,000
Secured Debt [Member] | Matures December 1, 2021, 5.98 Percent Interest Rate
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt				$ (1,930,000)
Reduction in secured borrowing balance				$ 52,710,000		$ 0
Interest rate | Rate				5.98%			5.98%
Long-term Debt								$ 500,000,000.0
Commercial Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Weighted average interest rate | Rate			3.226%			3.226%		4.789%
Debt weighted average to maturity, length						8 years 7 months 6 days		2 years 10 months 24 days
Total debt			$ 1,146,146,000			$ 1,146,146,000		$ 267,205,000
Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Net book value of properties securing collateralized term loans			$ 3,200,000,000			$ 3,200,000,000
Senior Unsecured NOtes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 600,000,000.0
Debt instrument term	10 years
Debt Instrument, Interest Rate, Stated Percentage	2.70%
Weighted average interest rate | Rate			2.70%			2.70%		0.00%
Debt weighted average to maturity, length						10 years		0 years
Proceeds from Issuance of Debt	$ 592,400,000
Unsecured Debt			$ 591,688,000			$ 591,688,000		$ 0
Term Loan [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument term		4 years
Line of credit, borrowing capacity			500,000,000.0			500,000,000.0			$ 1,000,000,000.0
Line of credit and other		$ 58,000,000.0	$ 39,600,000			$ 39,600,000		$ 45,000,000.0	$ 2,000,000,000.0
Term Loan [Member] | Revolving Credit Facility [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Basis points						0.85%
Term Loan [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points						0.725%
Term Loan [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points						1.40%
Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity, Incremental												$ 750,000,000.0
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Weighted average interest rate | Rate			0.928%			0.928%		2.107%
Debt weighted average to maturity, length						3 years 10 months 24 days		3 years 8 months 12 days
Long-term Debt								$ 652,000,000.0
Line of Credit [Member] | Revolving Credit Facility [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Debt Instrument, number of properties securing a debt instument | properties			31			31
Debt Instrument, Net Book Value of Property Securing Debt			$ 375,200,000			$ 375,200,000
Line of credit variable interest rate | Rate			1.20%			1.20%
Debt Instrument, Number of Sites Securing Debt | properties			5,165			5,165
Line of Credit [Member] | Term Loan [Member] | Minimum [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate | Rate								1.20%
Line of Credit [Member] | Term Loan [Member] | Maximum [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate | Rate			2.05%			2.05%
Senior Unsecured Notes1
Debt Instrument [Line Items]
Unsecured Debt			$ 591,700,000			$ 591,700,000
Properties securing debt [Member] | Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Sites, Wet Slips and Dry Storage Spaces | site			76,408			76,408
Debt Instrument, number of properties securing a debt instument | properties			192			192