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Mortgage Notes Payable and Credit Facility - Additional Information (Detail) |  | 1 Months Ended | 3 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Oct. 27, 2017 USD ($) | Oct. 31, 2015 USD ($) | Mar. 31, 2019 USD ($) mortgage property | Mar. 31, 2018 USD ($) | Dec. 31, 2018 USD ($) | Oct. 05, 2015 USD ($) | Aug. 31, 2013 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  |  | 101 |  |  |  |
Number of long-term mortgages repaid | mortgage |  |  | 1 |  |  |  |
Number of properties repaid to collateralized mortgages notes payable | property |  |  | 3 |  |  |  |
Payments of deferred financing costs |  |  | $ 279,000 | $ 212,000 |  |  |
Fair value of mortgage notes payable |  |  | 450,400,000 |  |  |  |
Maximum borrowing capacity | $ 75,000,000.0 |  |  |  |  |  | $ 25,000,000.0
Extension fee on initial maturity (as percent) | 0.25% |  |  |  |  |  |
Debt instrument fees incurred | $ 900,000 |  |  |  |  |  |
Line of credit outstanding |  |  | $ 32,335,000 |  | $ 50,084,000 |  |
Weighted average interest rate on debt outstanding (as percent) |  |  | 4.69% |  |  |  |
Term loan facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Term of debt | 5 years |  |  |  |  |  |
Extension fee on initial maturity (as percent) |  | 0.05% |  |  |  |  |
Revolving credit facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Term of debt | 4 years |  |  |  |  |  |
Line of credit |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Maximum borrowing capacity |  | $ 85,000,000.0 |  |  |  | $ 85,000,000.0 |
Line of credit outstanding |  |  | $ 107,800,000 |  |  |  |
Weighted average interest rate (as percent) |  |  | 4.21% |  |  |  |
Letters of credit, outstanding |  |  | $ 7,400,000 |  |  |  |
Maximum additional amount that can be drawn under Line of Credit |  |  | $ 39,500,000 |  |  |  |
Line of credit | Term loan facility |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Maximum borrowing capacity |  | $ 25,000,000.0 |  |  |  |  |
Term of debt |  | 5 years |  |  |  |  |
Letter of credit |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Weighted average interest rate on debt outstanding (as percent) |  |  | 1.75% |  |  |  |
Variable rate mortgage loans |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  |  | 18 |  |  |  |
Carrying value |  |  | $ 60,158,000 |  | 60,659,000 |  |
Mortgage notes payable |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Number of mortgage notes payable | mortgage |  |  | 48 |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  |  | 68 |  |  |  |
Net book value of collateralized mortgage properties |  |  | $ 647,000,000 |  |  |  |
Recourse amount of mortgage notes payable |  |  | $ 10,200,000 |  |  |  |
Percentage of debt recourse (as percent) |  |  | 2.30% |  |  |  |
Carrying value |  |  | $ 449,700,000 |  |  |  |
Weighted average interest rate on debt outstanding (as percent) |  |  | 4.60% |  |  |  |
Issued and assumed mortgage notes payable |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Number of mortgage notes payable | mortgage |  |  | 1 |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  |  | 1 |  |  |  |
Fixed rate mortgage loans |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  |  | 50 |  |  |  |
Stated interest rate (as percent) |  |  | 3.86% |  |  |  |
Payments of deferred financing costs |  |  | $ 300,000 | $ 200,000 |  |  |
Carrying value |  |  | $ 389,501,000 |  | $ 385,051,000 |  |
LIBOR |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Spread on LIBOR (as percent) | 2.75% |  |  |  |  |  |

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- Definition Amount of contractual principal due at origination of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Paragraph Column F -Subsection 29 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29(Column F)) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 + Details
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- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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