XML 194 R67.htm IDEA: XBRL DOCUMENT
v3.19.3

Other Investments - Safehold Inc. (Details) |  | 1 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 02, 2019 USD ($) director $ / shares shares | Aug. 31, 2019 USD ($) shares | Apr. 30, 2019 USD ($) | Feb. 28, 2019 | Jun. 30, 2018 USD ($) property lease facility | May 31, 2018 USD ($) office_building | Oct. 31, 2017 USD ($) | Sep. 30, 2019 USD ($) multiple shares | Sep. 30, 2018 USD ($) | Jun. 30, 2018 USD ($) property | Sep. 30, 2019 USD ($) multiple shares | Sep. 30, 2018 USD ($) | Jan. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Aug. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional cash investment in equity method investment |  |  |  |  |  |  |  |  |  |  | $ 494,339,000 | $ 68,666,000 |  |  |
Restriction period on common stock received as payment |  |  |  |  |  |  |  |  |  |  | 2 years |  |  |  |
Management agreement, termination fee as multiple of prior year management fee | multiple |  |  |  |  |  |  |  | 3 |  |  | 3 |  |  |  |
Management agreement, equity raised since inception metric related to renewal and termination |  |  |  |  |  |  |  | $ 820,000,000 |  |  | $ 820,000,000 |  |  |  |
Carrying value of loans |  |  |  |  |  |  |  | 686,762,000 |  |  | 686,762,000 |  |  | $ 919,493,000 |
Number of industrial facilities sold | facility |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |
Number of properties subject to ground leases | property |  |  |  |  | 2 |  |  |  |  | 2 |  |  |  |  |
Number of ground lease sold | lease |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |
Net proceeds from sales of real estate |  |  |  |  | $ 36,100,000 |  |  |  |  |  | 307,493,000 | 271,358,000 |  |  |
Income from sales of real estate |  |  |  |  | $ 24,500,000 |  |  | 3,476,000 | $ 5,409,000 |  | $ 233,406,000 | 79,353,000 |  |  |
Fee percent of SAFE Equity up to $1.5 billion |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee as percent of equity |  |  |  |  |  |  |  |  |  |  | 1.00% |  |  |  |
Fee percent of SAFE Equity up to $1.5 billion | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee equity threshold amount |  |  |  |  |  |  |  | 1,500,000,000 |  |  | $ 1,500,000,000 |  |  |  |
Fee percent of SAFE Equity between $1.5 billion and $3.0 billion |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee as percent of equity |  |  |  |  |  |  |  |  |  |  | 1.25% |  |  |  |
Fee percent of SAFE Equity between $1.5 billion and $3.0 billion | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee equity threshold amount |  |  |  |  |  |  |  | 1,500,000,000 |  |  | $ 1,500,000,000 |  |  |  |
Fee percent of SAFE Equity between $1.5 billion and $3.0 billion | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee equity threshold amount |  |  |  |  |  |  |  | 3,000,000,000.0 |  |  | $ 3,000,000,000.0 |  |  |  |
Fee percent of SAFE Equity between $3.0 billion and $5.0 billion |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee as percent of equity |  |  |  |  |  |  |  |  |  |  | 1.375% |  |  |  |
Fee percent of SAFE Equity between $3.0 billion and $5.0 billion | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee equity threshold amount |  |  |  |  |  |  |  | 3,000,000,000.0 |  |  | $ 3,000,000,000.0 |  |  |  |
Fee percent of SAFE Equity between $3.0 billion and $5.0 billion | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee equity threshold amount |  |  |  |  |  |  |  | 5,000,000,000.0 |  |  | $ 5,000,000,000.0 |  |  |  |
Fee percent of SAFE Equity over $5.0 billion |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee as percent of equity |  |  |  |  |  |  |  |  |  |  | 1.50% |  |  |  |
Fee percent of SAFE Equity over $5.0 billion | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee equity threshold amount |  |  |  |  |  |  |  | 5,000,000,000.0 |  |  | $ 5,000,000,000.0 |  |  |  |
SAFE | Real estate equity investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Investor Units purchased (in shares) | shares | 12,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investor Units, purchase price per unit (in dollars per share) | $ / shares | $ 20.00 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional cash investment in equity method investment | $ 250,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Voting power cap threshold (percent) | 41.90% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of director nominees | director | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Independent period | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |
Standstill provisions (in years) | 2 years |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exchange shares restriction period | 1 year |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock transfer limitation maximum per agreement, other than widely distributed public offering (percent) | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ground Lease, Atlanta medical office |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment to provide loan to lessee |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 24,000,000.0
Amount of loan funded |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 18,400,000
Interest income |  |  |  |  |  |  |  | 300,000 | 400,000 |  | 1,200,000 | 1,000,000.0 |  |  |
Multifamily Development San Jose |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of loan funded |  |  |  |  |  |  |  | 27,300,000 |  |  | 27,300,000 |  |  |  |
Interest income |  |  |  |  |  |  |  | 400,000 | 100,000 |  | 700,000 | 200,000 |  |  |
Lessor, operating lease, term of contract |  |  |  |  |  |  | 99 years |  |  |  |  |  |  |  |
Real estate, leasehold improvement allowance |  |  |  |  |  |  | $ 7,200,000 |  |  |  |  |  |  |  |
Forward purchase contract, purchase agreement, amount |  |  |  |  |  |  | 34,000,000.0 |  |  |  |  |  |  |  |
Ground Lease, Multi-tenant Office Atlanta |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment to provide loan to lessee |  |  |  |  |  | $ 19,900,000 |  |  |  |  |  |  |  |  |
Interest income |  |  |  |  |  |  |  | 500,000 | 600,000 |  | 1,600,000 | $ 800,000 |  |  |
Number of office buildings | office_building |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |
Ground Lease, Washington DC building conversion |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment to provide loan to lessee |  |  |  |  |  |  |  |  |  |  |  |  | $ 13,300,000 |  |
Amount of loan funded |  |  |  |  |  |  |  | 12,400,000 |  |  | 12,400,000 |  |  |  |
Interest income |  |  |  |  |  |  |  | 300,000 |  |  | 700,000 |  |  |  |
Leasehold First Mortgage | Multifamily Development San Jose |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment to provide loan to lessee |  |  |  |  |  |  | 80,500,000 |  |  |  |  |  |  |  |
Carrying value of loans |  |  |  |  |  |  | $ 80,500,000 |  |  |  |  |  |  |  |
SAFE |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, amount purchased |  |  | $ 34,300,000 |  |  |  |  |  |  |  |  |  |  |  |
Expense reimbursements from related party |  |  |  |  |  |  |  | 500,000 | 400,000 |  | 1,600,000 |  |  |  |
Expense reimbursement waived |  |  |  |  |  |  |  |  |  | $ 800,000 |  |  |  |  |
SAFE | Management Fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management fee revenue from related party |  |  |  |  |  |  |  | $ 1,900,000 | $ 900,000 |  | $ 5,000,000.0 |  |  |  |
Management fee revenue waived from related party |  |  |  |  |  |  |  |  |  | $ 1,800,000 |  |  |  |  |
SAFE |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ground lease term (in years) |  | 99 years |  | 98 years |  |  |  |  |  |  |  |  |  |  |
SAFE |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock received as payment of fees (in shares) | shares |  |  |  |  |  |  |  | 56,610 |  |  | 178,215 |  |  |  |
SAFE |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional cash investment in equity method investment |  | $ 168,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock company acquired (in shares) | shares |  | 6,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of ownership |  |  |  |  |  |  |  | 67.10% |  |  | 67.10% |  |  |  |

X
- Definition Business Acquisition, Number Of Shares Acquired + References No definition available. + Details
Name: | star_BusinessAcquisitionNumberOfSharesAcquired
Namespace Prefix: | star_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Common Stock Received As Payment Of Fees + References No definition available. + Details
Name: | star_CommonStockReceivedAsPaymentOfFees
Namespace Prefix: | star_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Common Stock Received As Payment, Restriction Period + References No definition available. + Details
Name: | star_CommonStockReceivedAsPaymentRestrictionPeriod
Namespace Prefix: | star_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Common Stock, Voting Rights, Investor Units Voting Power Threshold + References No definition available. + Details
Name: | star_CommonStockVotingRightsInvestorUnitsVotingPowerThreshold
Namespace Prefix: | star_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Forward Purchase Contract, Purchase Agreement, Amount + References No definition available. + Details
Name: | star_ForwardPurchaseContractPurchaseAgreementAmount
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Ground Leases Sold Number + References No definition available. + Details
Name: | star_GroundLeasesSoldNumber
Namespace Prefix: | star_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ground Leases, Term + References No definition available. + Details
Name: | star_GroundLeasesTerm
Namespace Prefix: | star_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investor Units, Purchase Price Per Unit + References No definition available. + Details
Name: | star_InvestorUnitsPurchasePricePerUnit
Namespace Prefix: | star_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Lessor, Operating Lease, Term of Contract1 + References No definition available. + Details
Name: | star_LessorOperatingLeaseTermofContract1
Namespace Prefix: | star_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reflects the aggregate gross carrying amount of all categories of loans held in portfolio, after deducting deferred income, but before deducting the allowance for losses on loans. + References No definition available. + Details
Name: | star_LoansReceivableNetOfDeferredIncome
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number Of Investor Units Purchased + References No definition available. + Details
Name: | star_NumberOfInvestorUnitsPurchased
Namespace Prefix: | star_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Office Buildings + References No definition available. + Details
Name: | star_NumberOfOfficeBuildings
Namespace Prefix: | star_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Industrial Facilities Sold + References No definition available. + Details
Name: | star_NumberofIndustrialFacilitiesSold
Namespace Prefix: | star_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Real Estate, Leasehold Improvement Allowance + References No definition available. + Details
Name: | star_RealEstateLeaseholdImprovementAllowance
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reimbursement Revenue Waived + References No definition available. + Details
Name: | star_ReimbursementRevenueWaived
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Related Party Transaction, Commitment to Extend Credit, Amount Funded + References No definition available. + Details
Name: | star_RelatedPartyTransactionCommitmenttoExtendCreditAmountFunded
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Related Party Transaction, Commitment to Extend Credit to Customer + References No definition available. + Details
Name: | star_RelatedPartyTransactionCommitmenttoExtendCredittoCustomer
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Related Party Transaction, Management Agreement, Renewal Clause, Equity Raised Since Inception + References No definition available. + Details
Name: | star_RelatedPartyTransactionManagementAgreementRenewalClauseEquityRaisedSinceInception
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Related Party Transaction, Management Agreement, Renewal Clause, Termination Fee As Multiple Of Prior Year Management Fee + References No definition available. + Details
Name: | star_RelatedPartyTransactionManagementAgreementRenewalClauseTerminationFeeAsMultipleOfPriorYearManagementFee
Namespace Prefix: | star_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Related Party Transaction, Management Fee, Percent of Equity + References No definition available. + Details
Name: | star_RelatedPartyTransactionManagementFeePercentofEquity
Namespace Prefix: | star_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Related Party Transaction, Management Fee, Shareholders' Equity Threshold Amount + References No definition available. + Details
Name: | star_RelatedPartyTransactionManagementFeeShareholdersEquityThresholdAmount
Namespace Prefix: | star_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Stock Transfer Limitation Per Agreement, Other Than Widely Distributed Public Offering, Maximum Percentage + References No definition available. + Details
Name: | star_StockTransferLimitationPerAgreementOtherThanWidelyDistributedPublicOfferingMaximumPercentage
Namespace Prefix: | star_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Stockholders Agreement, Director Nominees + References No definition available. + Details
Name: | star_StockholdersAgreementDirectorNominees
Namespace Prefix: | star_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Stockholders Agreement, Director Nominees, Independent Period + References No definition available. + Details
Name: | star_StockholdersAgreementDirectorNomineesIndependentPeriod
Namespace Prefix: | star_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Stockholders Agreement, Exchange Shares, Restriction Period + References No definition available. + Details
Name: | star_StockholdersAgreementExchangeSharesRestrictionPeriod
Namespace Prefix: | star_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Stockholders Agreement Standstill Provision Term + References No definition available. + Details
Name: | star_StockholdersAgreementStandstillProvisionTerm
Namespace Prefix: | star_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477 + Details
Name: | us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of voting equity interests acquired in a business combination achieved in stages, including equity interests in the acquiree held by the acquirer immediately before the acquisition date and acquired at the acquisition date. + References No definition available. + Details
Name: | us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeIncludingSubsequentAcquisitionPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2443-110228 + Details
Name: | us-gaap_GainLossOnSaleOfProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of interest income earned from interest-bearing assets owed to the entity by related party. + References No definition available. + Details
Name: | us-gaap_InterestIncomeRelatedParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of separate real estate development properties located on land subject to ground leases. + References No definition available. + Details
Name: | us-gaap_NumberOfPropertiesSubjectToGroundLeases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Cash received for the sale of real estate that is not part of an investing activity during the current period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfRealEstate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Direct costs arising from transactions with related parties who are not affiliates or joint Ventures. These costs are categorized as cost of goods sold. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(k)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_RelatedPartyCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period. + References No definition available. + Details
Name: | us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07.1(c)) -URI http://asc.fasb.org/extlink&oid=114873854&loc=SL114874292-224272 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 + Details
Name: | us-gaap_RevenueFromRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | star_ManagementAgreementFeeStructureAxis=star_ManagementFeeTrancheOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | star_ManagementAgreementFeeStructureAxis=star_ManagementFeeTrancheTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | star_ManagementAgreementFeeStructureAxis=star_ManagementFeeTrancheThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | star_ManagementAgreementFeeStructureAxis=star_ManagementFeeTrancheFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=star_SafeholdInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_RealEstateInvestmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=star_GroundLeaseAtlantaMedicalCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=star_GroundLeaseMultifamilyDevelopmentSanJoseCAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=star_GroundLease100200GlenridgePointAtlantaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=star_GroundLeaseConversionWashingtonDCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=star_LeaseholdFirstMortgageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_AffiliatedEntityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_ManagementServiceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=star_SafeholdInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=star_SafeholdInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=star_SafeholdInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |