Low Income Housing Tax Credits (Details) $ in Thousands	Sep. 30, 2017 USD ($) housing_equity_fund	Dec. 31, 2016 USD ($) housing_equity_fund
Schedule of Equity Method Investments [Line Items]
Number of housing equity funds | housing_equity_fund	5	5
Other Assets
Schedule of Equity Method Investments [Line Items]
Investments in housing equity funds	$ 10,600	$ 664
Other Liabilities
Schedule of Equity Method Investments [Line Items]
Additional capital calls expected	$ 6,150