Other Borrowings (Trust Preferred Offerings) (Details) (USD $)	12 Months Ended																	12 Months Ended			12 Months Ended						12 Months Ended								0 Months Ended
	Dec. 31, 2013 subsidiary	Dec. 31, 2012	Mar. 07, 2012 Trust Preferred Capital Securities	Dec. 31, 2013 Interest Rate Swap	Dec. 31, 2013 Trust Preferred Securities	Dec. 31, 2012 Trust Preferred Securities	Dec. 31, 2013 Senior Notes	Dec. 31, 2012 Senior Notes	Dec. 31, 2013 Senior Notes December 1, 2015	Dec. 31, 2013 Senior Notes February 1, 2017	Dec. 31, 2013 Senior Notes February 1, 2018	Dec. 31, 2013 Senior Notes February 1, 2019	Dec. 31, 2013 Tier 1 Trust Preferred Securities	Dec. 31, 2012 Tier 1 Trust Preferred Securities	Dec. 31, 2013 Heartland Financial Statutory Trust III Trust Preferred Securities		Dec. 31, 2013 Heartland Financial Statutory Trust IV Interest Rate Swap	Dec. 31, 2013 Heartland Financial Statutory Trust IV Trust Preferred Securities		Dec. 31, 2013 Heartland Financial Statutory Trust V Interest Rate Swap	Dec. 31, 2013 Heartland Financial Statutory Trust V Trust Preferred Securities		Dec. 31, 2013 Heartland Financial Statutory Trust VI Interest Rate Swap	Dec. 31, 2013 Heartland Financial Statutory Trust VI Trust Preferred Securities		Dec. 31, 2013 Heartland Financial Statutory Trust VII Interest Rate Swap	Dec. 31, 2013 Heartland Financial Statutory Trust VII Trust Preferred Securities		Dec. 31, 2013 Morrill Statutory Trust I Trust Preferred Securities		Dec. 31, 2013 Morrill Statutory Trust II Trust Preferred Securities		Dec. 31, 2013 Morrill subsidiary	Apr. 20, 2011 Bank One Loans Payable	Apr. 20, 2011 Interest Rate Swap Bank One
Debt Instrument [Line Items]
Number of wholly-owned trust subsidiaries that issue preferred securities	7																																2
Deferred issuance costs					$ 158,000
Long-term debt	350,109,000	389,025,000			124,860,000	108,250,000	37,500,000	37,500,000					124,900,000	108,300,000	20,619,000			25,774,000			20,619,000			20,619,000			20,619,000		8,524,000		8,086,000			15,000,000
Stated interest rate, percent			10.60%				5.00%								8.25%									6.75%
Basis spread on variable rate																		2.75%			1.33%						1.48%		3.25%		2.85%
Description of variable rate basis																		LIBOR			LIBOR						LIBOR		LIBOR		LIBOR
Interest rate															8.25%	[1]		2.99%	[1],[2]		1.57%	[1],[3]		6.75%	[1],[4]		1.72%	[1],[5]	3.50%	[1]	3.09%	[1]
Fixed interest rate on derivative				5.85%													5.33%			4.69%			1.48%			4.70%									5.14%
Debt instrument, maturity amount									17,500,000	7,000,000	7,000,000	6,000,000
Senior notes	37,500,000	37,500,000
Preferred stock, call or exercise features			5,000,000
Prepayment obligation exercising call option			238,000
Unamortized debt issuance expense			$ 64,000
Derivative maturity																																			5 years

[1] Effective weighted average interest rate as of December 31, 2012, was 5.85% due to interest rate swap transactionson the variable rate securities as discussed in Note 12 to Heartland's consolidated financial statements.

[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.