Notes Receivable from Partners - Additional Information (Detail) - Partners - USD ($) |
9 Months Ended | ||||
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Sep. 30, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Aug. 31, 2009 |
Jan. 31, 2008 |
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| Related Party Transaction [Line Items] | |||||
| Term of promissory notes receivable | in the form of five or six year interest-bearing promissory notes and/or in the form of nine year interest-bearing limited recourse promissory notes | ||||
| Notes receivable from partners | $ 921,000 | $ 1,918,000 | $ 2,085,000 | ||
| Allowance for credit losses on notes receivable | 0 | 0 | |||
| Limited Recourse | |||||
| Related Party Transaction [Line Items] | |||||
| Interest rates of promissory notes | 2.77% | 3.53% | |||
| Notes receivable from partners | 0 | 825,000 | |||
| Full Recourse | |||||
| Related Party Transaction [Line Items] | |||||
| Notes receivable from partners | $ 921,000 | $ 1,093,000 |
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition A valuation allowance for financing receivables that are expected to be uncollectible. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- 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. No definition available.
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- Definition Description of the terms and manner of settlement of the related party transaction. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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