For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Subsequent Events (Details) - USD ($) $ in Millions		6 Months Ended
Subsequent Events (Details) - USD ($) $ in Millions	Aug. 01, 2018	Jun. 30, 2018
Subsequent Event [Line Items]
Classified assets to bank capital as a percent		52.90%
Concentration risk (as a percent)		10.00%
Customer Concentration Risk \| Loans and Lease Receivable \| Energy Loans
Subsequent Event [Line Items]
Concentration risk (as a percent)		14.50%
Pro Forma
Subsequent Event [Line Items]
Classified assets to bank capital as a percent		47.90%
Pro Forma \| Customer Concentration Risk \| Loans and Lease Receivable \| Energy Loans
Subsequent Event [Line Items]
Concentration risk (as a percent)		1.38%
Subsequent Event
Subsequent Event [Line Items]
Payoff payment received	$ 8.5