Reportable Segments and Related Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 item	Mar. 31, 2013	Dec. 31, 2013
Reportable Segments and Related Information
Number of reportable segments	3
Reportable Segments and Related Information
Goodwill	$ 20,686		$ 20,686
Total Assets	3,542,061		3,539,575
Interest Income	26,251	27,115
Interest Expense	1,694	2,532
Other Income	14,986	16,641
Net Income	7,887	6,433
Operating segments | Busey Bank
Reportable Segments and Related Information
Total Assets	3,458,868		3,456,555
Interest Income	26,181	27,040
Interest Expense	1,410	2,232
Other Income	8,536	10,497
Net Income	7,279	5,793
Operating segments | FirsTech
Reportable Segments and Related Information
Goodwill	8,992		8,992
Total Assets	27,482		27,253
Interest Income	12	13
Other Income	2,387	2,129
Net Income	309	262
Operating segments | Busey Wealth Management
Reportable Segments and Related Information
Goodwill	11,694		11,694
Total Assets	28,467		28,548
Interest Income	64	60
Other Income	4,541	4,103
Net Income	1,002	820
All other
Reportable Segments and Related Information
Total Assets	27,244		27,219
Interest Income	(6)	2
Interest Expense	284	300
Other Income	(478)	(88)
Net Income	$ (703)	$ (442)