Variable Interest Entities (VIE) (Narrative) (Details) - USD ($) $ in Thousands |
1 Months Ended | 9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Nov. 30, 2009 |
Sep. 30, 2017 |
Dec. 31, 2011 |
Dec. 31, 2009 |
Dec. 31, 2016 |
|
| Variable Interest Entity [Line Items] | |||||
| Long-term Debt | $ 120,929 | $ 131,737 | |||
| Payments to Acquire Businesses and Interest in Affiliates | $ 6,100 | $ 6,100 | |||
| VIE purpose | purchase the land and construct a 36-unit low income housing rental complex | ||||
| Federal investment tax credits | $ 8,400 | ||||
| Change in federal investment tax credits | $ (600) | ||||
| Federal investment tax credit duration | 10 years | ||||
| Variable Interest Entity, Not Primary Beneficiary [Member] | |||||
| Variable Interest Entity [Line Items] | |||||
| Long-term Debt | 30,900 | ||||
| Equity Method Investments | 900 | ||||
| Ownership in Liberty Mews Limited Partnership | 99.99% | ||||
| VIE financing | 10,600 | ||||
| Construction and Development Costs | $ 10,600 | ||||
| Partnership total assets | $ 8,600 | $ 8,800 | |||