Other Borrowings (Trust Preferred Offerings) (Details) (USD $)	12 Months Ended													12 Months Ended			12 Months Ended						12 Months Ended
	Dec. 31, 2012 subsidiary	Dec. 31, 2011	Dec. 31, 2012 Interest Rate Swap	Dec. 31, 2012 Trust preferred securities	Dec. 31, 2011 Trust preferred securities	Dec. 31, 2012 Senior Notes	Dec. 31, 2011 Senior Notes	Mar. 11, 2011 Senior Notes	Dec. 31, 2012 Tier 1 Trust preferred securities	Dec. 31, 2011 Tier 1 Trust preferred securities	Dec. 31, 2012 Heartland Financial Statutory Trust III Trust preferred securities		Dec. 31, 2012 Heartland Financial Statutory Trust IV Interest Rate Swap	Dec. 31, 2012 Heartland Financial Statutory Trust IV Trust preferred securities		Dec. 31, 2012 Heartland Financial Statutory Trust V Interest Rate Swap	Dec. 31, 2012 Heartland Financial Statutory Trust V Trust preferred securities		Dec. 31, 2012 Heartland Financial Statutory Trust VI Interest Rate Swap	Dec. 31, 2012 Heartland Financial Statutory Trust VI Trust preferred securities		Dec. 31, 2012 Heartland Financial Statutory Trust VII Interest Rate Swap	Dec. 31, 2012 Heartland Financial Statutory Trust VII Trust preferred securities		Dec. 31, 2012 Senior Note, Portion 3 Senior Notes
Debt Instrument [Line Items]
Number of wholly-owned trust subsidiaries that issue preferred securities	5
Deferred issuance costs				$ 166,000
Long-term debt	389,025,000	372,820,000		108,250,000	113,405,000	37,500,000	27,500,000		108,300,000	112,700,000	20,619,000			25,774,000			20,619,000			20,619,000			20,619,000
Stated interest rate, percent								5.00%			8.25%									6.75%
Interest rate											8.25%	[1]		3.30%	[1],[2]		1.73%	[1],[3]		6.75%	[1],[4]		2.01%	[1],[5]
Description of variable rate basis														LIBOR			LIBOR						LIBOR
Basis spread on variable rate														2.75%			1.33%						1.48%
Fixed interest rate on derivative			5.91%										5.33%			4.69%			1.48%			4.70%
Debt instrument, maturity amount																									$ 7,000,000

[1] Interest rates are fixed with the exception of the interest rate on the $20.0 million transaction with Citigroup Global Markets.

[2] Effective interest rate as of December 31, 2012, was 5.33% due to an interest rate swap transaction as discussed inNote 12 to Heartland's consolidated financial statements.

[3] Effective interest rate as of December 31, 2012, was 4.69% due to an interest rate swap transaction as discussed inNote 12 to Heartland's consolidated financial statements.

[4] Interest rate is fixed at 6.75% through June 15, 2017 then resets to 1.48% over LIBOR for the remainder of the term.

[5] Effective interest rate as of December 31, 2012, was 4.70% due to an interest rate swap transaction as discussed inNote 12 to Heartland's consolidated financial statements.