Variable Interest Entities Amortization Expense and Tax Credits and Other Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Investments in Qualified Affordable Housing Projects
Amortization expense	$ 1,609	$ 1,177	$ 4,504	$ 3,098
Tax credits and other tax benefits recognized	$ 2,202	$ 1,651	$ 6,169	$ 4,314

Amount of amortization expense of investment in qualified affordable housing projects.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration