Basis of Presentation	6 Months Ended
Basis of Presentation	Jun. 30, 2013
Basis of Presentation [Abstract]
Basis of Presentation	Note 1 - Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments, consisting of normal recurring accruals, considered necessary for a fair presentation have been included. All share and per share data have been restated to give effect to the 10% stock dividend issued on December 14, 2012. For further information, refer to the audited consolidated financial statements and related footnotes included in Cass Information System, Inc.'s (the "Company" or "Cass") Annual Report on Form 10-K for the year ended December 31, 2012.

The entire disclosure for all significant accounting policies of the reporting entity.