Parent Company Only Financial Information (Income Statements) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating revenues:
Securities gains, net									$ 3,668	$ 7,121	$ 13,998
Operating expenses:
Interest									33,969	35,683	39,182
Salaries and benefits									129,843	118,224	105,727
Professional fees									18,241	17,532	15,338
Income (loss) before income taxes									54,996	47,188	67,235
Income tax benefit	(4,327)	(2,916)	(4,150)	(1,703)	(46)	(1,492)	(3,598)	(5,199)	(13,096)	(10,335)	(17,384)
NET INCOME ATTRIBUTABLE TO HEARTLAND	12,263	11,973	10,774	6,890	7,935	6,810	9,556	12,488	41,900	36,789	49,792
Preferred dividends and discount	(204)	(205)	(204)	(204)	(204)	(276)	(205)	(408)	(817)	(1,093)	(3,400)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	12,059	11,768	10,570	6,686	7,731	6,534	9,351	12,080	41,083	35,696	46,392
Parent
Operating revenues:
Dividends from subsidiaries									47,485	47,750	42,800
Securities gains, net									0	2,316	0
Gain (loss) on trading account securities									(38)	1,421	47
Other									640	726	664
Total operating revenues									48,087	52,213	43,511
Operating expenses:
Interest									10,052	9,206	9,133
Salaries and benefits									5,584	5,104	6,191
Professional fees									3,406	3,671	3,100
Other operating expenses									2,173	1,577	2,417
Total operating expenses									21,215	19,558	20,841
Equity in undistributed earnings (losses)									6,749	(1,275)	19,739
Income (loss) before income taxes									33,621	31,380	42,409
Income tax benefit									8,279	5,409	7,383
NET INCOME ATTRIBUTABLE TO HEARTLAND									41,900	36,789	49,792
Preferred dividends and discount									(817)	(1,093)	(3,400)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS									$ 41,083	$ 35,696	$ 46,392