Subsequent Events (Details) - Subsequent Event $ in Millions	Oct. 15, 2021 USD ($)
Subsequent Event [Line Items]
Repayments of subordinated debt	$ 278.8
NTC Capital I Subordinated Debentures Due January 15th 2027
Subsequent Event [Line Items]
Repayments of subordinated debt	154.9
NTC Capital II Subordinated Debentures Due April 15th 2027
Subsequent Event [Line Items]
Repayments of subordinated debt	$ 123.9

The cash outflow from the repayment of long-term borrowing where a lender is placed in a lien position behind debt having a higher priority of repayment (senior) in case of liquidation of the entity's assets or underlying collateral.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3291-108585

Name:	us-gaap_RepaymentsOfSubordinatedDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration