NOTE 8 - BUSINESS SEGMENT INFORMATION - (Details) $ in Thousands	Sep. 30, 2020 USD ($) subsidiary
Number of subsidiaries commercial banks	4
Commercial Banking
Number of subsidiaries commercial banks	4
Wealth Management Segment [Member]
Assets allocated \| $	$ 0

The amount of assets of subsidiary banks allocated to other segments.

No definition available.

Name:	qcrh_AssetsOfSubsidiaryBanksAllocated
Namespace Prefix:	qcrh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant