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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Part 4 (Details) - USD ($) |  |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
May 02, 2018 | Jun. 28, 2017 | May 03, 2017 | May 04, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 09, 2015
Stock Compensation Plans [Abstract] |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  |  | 0 | 0 | 0 |
Unrecognized expense related to non-vested awards of restricted shares granted |  |  |  |  | $ 64,000 |  |  |
Granted, restricted stock awards (in shares) |  |  |  | 5,000 |  |  |  |
Fair market value (in dollars per share) |  |  |  | $ 27.70 |  |  |  |
Award vesting period |  |  |  | 1 year |  |  |  |
Accounts Receivable [Abstract] |  |  |  |  |  |  |  |
Expense related to allowance for doubtful accounts |  |  |  |  | 100,000 | $ 200,000 |  |
Summary of changes in entity's accounts receivable [Abstract] |  |  |  |  |  |  |  |
Gross accounts receivable |  |  |  |  | 8,391,000 | 9,185,000 | $ 8,059,000 |
Less allowance for doubtful accounts |  |  |  |  | 232,000 | 288,000 | 263,000 |
Total Accounts Receivable |  |  |  |  | 8,159,000 | 8,897,000 | 7,796,000 |
Summary of allowance for doubtful accounts [Abstract] |  |  |  |  |  |  |  |
Beginning balance |  |  |  |  | 288,000 | 263,000 | 277,000 |
Allowance adjustments |  |  |  |  | 103,000 | 215,000 | 195,000 |
Recoveries |  |  |  |  | 47,000 | 41,000 | 64,000 |
Write off of uncollectible accounts |  |  |  |  | (206,000) | (231,000) | (273,000) |
Ending balance |  |  |  |  | $ 232,000 | 288,000 | 263,000 |
Cash and Cash Equivalents [Abstract] |  |  |  |  |  |  |  |
Maximum maturity period of temporary cash investments considered as cash equivalents |  |  |  |  | 3 months |  |  |
Restricted Stock [Member] |  |  |  |  |  |  |  |
Stock Compensation Plans [Abstract] |  |  |  |  |  |  |  |
Compensation costs |  |  |  |  | $ 192,000 | 423,000 | 92,000 |
Class A Stock [Member] | 2015 Equity Compensation Plan [Member] |  |  |  |  |  |  |  |
Stock Compensation Plans [Abstract] |  |  |  |  |  |  |  |
Number of share authorize under equity compensation plan (in shares) |  |  |  |  |  |  |  | 331,500
Class A Stock [Member] | Unrestricted Stock [Member] | 2015 Equity Compensation Plan [Member] |  |  |  |  |  |  |  |
Stock Compensation Plans [Abstract] |  |  |  |  |  |  |  |
Granted, restricted stock awards (in shares) |  | 6,568 |  |  |  |  |  |
Fair market value (in dollars per share) |  | $ 38.06 |  |  |  |  |  |
Class A Stock [Member] | Restricted Stock [Member] | 2015 Equity Compensation Plan [Member] |  |  |  |  |  |  |  |
Stock Compensation Plans [Abstract] |  |  |  |  |  |  |  |
Granted, restricted stock awards (in shares) | 5,000 |  | 5,000 |  |  |  |  |
Fair market value (in dollars per share) | $ 38.51 |  | $ 38.10 |  |  |  |  |
Award vesting period |  |  |  |  | 1 year |  |  |
Customer accounts receivable - water [Member] |  |  |  |  |  |  |  |
Summary of changes in entity's accounts receivable [Abstract] |  |  |  |  |  |  |  |
Gross accounts receivable |  |  |  |  | $ 5,585,000 | 5,487,000 | 5,437,000 |
Contractual amounts due from developers and other [Member] |  |  |  |  |  |  |  |
Summary of changes in entity's accounts receivable [Abstract] |  |  |  |  |  |  |  |
Gross accounts receivable |  |  |  |  | $ 2,806,000 | $ 3,698,000 | $ 2,622,000 |

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