Basis of Presentation (Earnings per share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share
Net income attributable to Heartland	$ 20,970	$ 15,160	$ 40,979	$ 30,869
Preferred dividends	(52)	(204)	(220)	(408)
Interest expense on convertible preferred debt	31	0	31	0
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 20,949	$ 14,956	$ 40,790	$ 30,461
Weighted average common shares outstanding for basic earnings per share	24,524	20,599	24,093	20,408
Assumed incremental common shares issued upon exercise of stock options and non-vested restricted stock units	451	278	448	274
Weighted average common shares for diluted earnings per share	24,975	20,877	24,541	20,682
Earnings per common share — basic (in dollars per share)	$ 0.85	$ 0.73	$ 1.69	$ 1.49
Earnings per common share — diluted (in dollars per share)	$ 0.84	$ 0.72	$ 1.66	$ 1.47
Number of antidilutive common stock equivalents excluded from diluted earnings per share computation (in shares)	0	0	0	0