v2.4.0.6
DOCUMENT AND ENTITY INFORMATION
3 Months Ended
Mar. 31, 2013
Apr. 29, 2013
Entity Registrant Name CASS INFORMATION SYSTEMS INC  
Entity Central Index Key 0000708781  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Trading Symbol cass  
Entity Common Stock, Shares Outstanding   11,487,650
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2013  
Document Fiscal Period Focus Q1  
Document Fiscal Year Focus 2013