Subsequent Events	9 Months Ended
Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Note 13 – Subsequent Events On October 24, 2017, the Company’s board of directors declared a 10% common stock dividend payable on December 15, 2017 to shareholders of record on December 5, 2017. Shareholders will receive one additional share of Cass common stock for each 10 shares of common stock owned. No fractional shares will be issued. Shareholders will receive cash for any fractional shares owned based on the share price reported by the Nasdaq Stock Market at the close of trading on December 5, 2017. Additionally, on October 24, 2017, the Company’s board of directors declared a fourth quarter cash dividend of $0.24 per share payable on December 15, 2017 to shareholders of record on December 5, 2017. The cash dividend will apply to all shares of common stock held after the 10% common stock dividend is completed.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration