Tax Credit Investments - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other Assets
Other Assets:
Affordable housing tax credit investments, net	$ 38,807	$ 22,135
Other tax credit investments, net	33,440	42,015
Total tax credit investments, net	72,247	64,150
Other Liabilities
Other Liabilities:
Unfunded affordable housing tax credit commitments	4,628	3,690
Unfunded other tax credit commitments	9,071	15,020
Total unfunded tax credit commitments	$ 13,699	$ 18,710