XML 83 R71.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Note 19 - Stock Repurchase Program (Details Textual) - February 2016 Repurchase Program [Member] - shares shares in Millions | Jun. 30, 2018 | Dec. 31, 2017 | Feb. 01, 2016
--- | --- | --- | ---
Stock Repurchase Program, Number of Shares Authorized to be Repurchased |  |  | 45.0
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased | 7.5 | 7.5 |

X
- Definition The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ShareRepurchaseProgramAxis=caty_February2016RepurchaseProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |