Heartland Financial USA (HTLF) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 02, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	HEARTLAND FINANCIAL USA INC
Entity Central Index Key	920,112
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		34,473,352

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 196,847	$ 168,723
Interest bearing deposits with the Federal Reserve Bank and other banks and other short-term investments	240,528	27,280
Cash and cash equivalents	437,375	196,003
Time deposits in other financial institutions	5,836	9,820
Securities:
Carried at fair value (cost of $2,342,977 at September 30, 2018, and $2,248,181 at December 31, 2017)	2,274,215	2,216,753
Held to maturity, at cost (fair value of $247,394 at September 30, 2018, and $265,494 at December 31, 2017)	239,908	253,550
Other investments, at cost	26,656	22,563
Loans held for sale	77,727	44,560
Loans receivable:
Held to maturity	7,365,493	6,391,464
Allowance for loan and lease losses	(61,221)	(55,686)
Loans receivable, net	7,304,272	6,335,778
Premises, furniture and equipment, net	193,802	172,324
Premises, furniture and equipment held for sale	4,422	1,977
Other real estate, net	11,908	10,777
Goodwill	391,668	236,615
Core deposit intangibles and customer relationship intangibles, net	50,071	35,203
Servicing rights, net	32,039	25,857
Cash surrender value on life insurance	162,216	142,818
Other assets	123,017	106,141
TOTAL ASSETS	11,335,132	9,810,739
Deposits:
Demand	3,427,819	2,983,128
Savings	4,958,430	4,240,328
Time	1,125,914	923,453
Total deposits	9,512,163	8,146,909
Deposits held for sale	50,312	0
Short-term borrowings	131,139	324,691
Other borrowings	277,563	285,011
Accrued expenses and other liabilities	83,562	62,671
TOTAL LIABILITIES	10,054,739	8,819,282
STOCKHOLDERS' EQUITY:
Common stock (par value $1 per share; 40,000,000 shares authorized at both September 30, 2018, and December 31, 2017; issued 34,473,029 shares at September 30, 2018, and 29,953,356 shares at December 31, 2017)	34,473	29,953
Capital surplus	742,080	503,709
Retained earnings	553,662	481,331
Accumulated other comprehensive loss	(49,822)	(24,474)
Treasury stock at cost (0 shares at both September 30, 2018, and December 31, 2017)	0	0
TOTAL STOCKHOLDERS' EQUITY	1,280,393	991,457
TOTAL LIABILITIES AND EQUITY	11,335,132	9,810,739
Preferred Stock
STOCKHOLDERS' EQUITY:
Preferred stock	0	0
Series A Junior Participating Preferred Stock
STOCKHOLDERS' EQUITY:
Preferred stock	0	0
Series C Senior Non-Cumulative Perpetual Preferred Stock
STOCKHOLDERS' EQUITY:
Preferred stock	0	0
Series D Senior Non-Cumulative Perpetual Preferred Stock
STOCKHOLDERS' EQUITY:
Preferred stock	$ 0	$ 938

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Cost of available for sale securities	$ 2,342,977	$ 2,248,181
Fair value of held to maturity securities	$ 247,394	$ 265,494
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	34,473,029	29,953,356
Treasury stock (in shares)	0	0
Preferred Stock
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	17,604	17,604
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series A Junior Participating Preferred Stock
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	16,000	16,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series C Senior Non-Cumulative Perpetual Preferred Stock
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	81,698	81,698
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series D Senior Non-Cumulative Perpetual Preferred Stock
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	3,000	3,000
Preferred stock, shares issued (in shares)	0	745
Preferred stock, shares outstanding (in shares)	0	745

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
INTEREST INCOME:
Interest and fees on loans	$ 105,733	$ 82,906	$ 288,171	$ 217,898
Interest on securities:
Taxable	14,433	10,394	38,280	27,246
Nontaxable	3,490	5,086	10,653	15,297
Interest on federal funds sold	0	34	0	37
Interest on interest bearing deposits in other financial institutions	1,238	558	2,413	1,112
TOTAL INTEREST INCOME	124,894	98,978	339,517	261,590
INTEREST EXPENSE:
Interest on deposits	10,092	5,073	23,841	12,966
Interest on short-term borrowings	464	271	1,279	498
Interest on other borrowings (includes $242 and $308 of interest expense related to derivatives reclassified from accumulated other comprehensive income for the three months ended September 30, 2018 and 2017, respectively, and $469 and $1,005 of interest expense related to derivatives reclassified from accumulated other comprehensive income for the nine months ended September 30, 2018 and 2017, respectively)	3,660	3,790	10,726	10,674
TOTAL INTEREST EXPENSE	14,216	9,134	35,846	24,138
NET INTEREST INCOME	110,678	89,844	303,671	237,452
Provision for loan losses	5,238	5,705	14,332	10,235
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	105,440	84,139	289,339	227,217
NONINTEREST INCOME:
Revenue from contract with customers	18,505	14,960	51,735	43,735
Loan servicing income	1,670	1,161	5,231	4,236
Securities gains/(losses), net (includes $145 of net security losses and $1,679 of net security gains reclassified from accumulated other comprehensive income for the three months ended September 30, 2018 and 2017, respectively, and $1,037 and $5,553 of net security gains reclassified from accumulated other comprehensive income for the nine months ended September 30, 2018 and 2017, respectively)	(145)	1,679	1,037	5,553
Unrealized gain on equity securities, net	54	0	97	0
Net gains on sale of loans held for sale	7,410	4,997	18,261	17,961
Valuation allowance on commercial servicing rights	230	5	12	29
Income on bank owned life insurance	892	766	2,206	2,039
Other noninterest income	1,149	1,409	3,536	2,941
TOTAL NONINTEREST INCOME	29,765	24,977	82,115	76,494
NONINTEREST EXPENSES:
Salaries and employee benefits	49,921	45,225	149,389	128,118
Occupancy	6,348	6,223	18,706	16,352
Furniture and equipment	3,470	2,826	9,403	7,913
Professional fees	11,681	8,450	30,088	24,342
FDIC insurance assessments	1,119	894	2,792	2,610
Advertising	2,754	1,358	6,839	5,141
Core deposit intangibles and customer relationship intangibles amortization	2,626	1,863	6,763	4,252
Other real estate and loan collection expenses	784	581	2,464	1,774
Loss on sales/valuations of assets, net	912	1,342	2,243	1,642
Restructuring expenses	0	0	2,564	0
Other noninterest expenses	12,924	9,997	33,816	27,653
TOTAL NONINTEREST EXPENSES	92,539	78,759	265,067	219,797
INCOME BEFORE INCOME TAXES	42,666	30,357	106,387	83,914
Income taxes (includes $(26) and $511 of income tax expense/(benefit) reclassified from accumulated other comprehensive income for the three months ended September 30, 2018 and 2017, respectively, and $174 and $1,696 of income tax expense/(benefit) reclassified from accumulated other comprehensive income for the nine months ended September 30, 2018 and 2017, respectively)	8,956	8,725	21,530	22,314
NET INCOME	33,710	21,632	84,857	61,600
Preferred dividends	(13)	(13)	(39)	(45)
Interest expense on convertible preferred debt	0	3	0	12
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 33,697	$ 21,622	$ 84,818	$ 61,567
EARNINGS PER COMMON SHARE - BASIC (in dollars per share)	$ 0.98	$ 0.73	$ 2.61	$ 2.23
EARNINGS PER COMMON SHARE - DILUTED (in dollars per share)	0.97	0.72	2.59	2.21
CASH DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.14	$ 0.11	$ 0.40	$ 0.33
Service charges and fees
NONINTEREST INCOME:
Revenue from contract with customers	$ 12,895	$ 10,138	$ 35,046	$ 29,291
Trust fees
NONINTEREST INCOME:
Revenue from contract with customers	4,499	3,872	13,794	11,482
Brokerage and insurance commissions
NONINTEREST INCOME:
Revenue from contract with customers	$ 1,111	$ 950	$ 2,895	$ 2,962

CONSOLIDATED STATEMENTS OF IN_2

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest expense related to derivatives reclassified from accumulated other comprehensive income	$ 3,660	$ 3,790	$ 10,726	$ 10,674
Net security gains reclassified from accumulated other comprehensive income	(145)	1,679	1,037	5,553
Income tax expense (benefit) reclassified from accumulated other comprehensive income	8,956	8,725	21,530	22,314
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Derivatives
Interest expense related to derivatives reclassified from accumulated other comprehensive income	242	308	469	1,005
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Unrealized Investment Gain (Loss)
Net security gains reclassified from accumulated other comprehensive income	145	1,679	1,037	5,553
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Other Comprehensive Income (Loss)
Income tax expense (benefit) reclassified from accumulated other comprehensive income	$ (26)	$ 511	$ 174	$ 1,696

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 33,710	$ 21,632	$ 84,857	$ 61,600
Securities:
Net change in unrealized gain (loss) on securities	(8,060)	6,940	(36,395)	22,002
Reclassification adjustment for net (gains)/losses realized in net income	145	(1,679)	(1,037)	(5,553)
Income taxes	2,078	(2,084)	9,586	(6,433)
Other comprehensive income (loss) on securities	(5,837)	3,177	(27,846)	10,016
Derivatives used in cash flow hedging relationships:
Net change in unrealized gain (loss) on derivatives	395	17	2,991	(656)
Reclassification adjustment for net losses on derivatives realized in net income	242	308	469	1,005
Income taxes	(79)	(123)	(682)	(337)
Other comprehensive income on cash flow hedges	558	202	2,778	12
Other comprehensive income (loss)	(5,279)	3,379	(25,068)	10,028
TOTAL COMPREHENSIVE INCOME	$ 28,431	$ 25,011	$ 59,789	$ 71,628

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 84,857	$ 61,600
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,647	22,738
Provision for loan losses	14,332	10,235
Net amortization of premium on securities	18,958	20,186
Securities gains, net	(1,037)	(5,553)
Unrealized gain on equity securities, net	(97)	0
Stock based compensation	3,689	3,588
Loans originated for sale	(551,328)	(548,768)
Proceeds on sales of loans held for sale	594,529	586,202
Net gains on sale of loans held for sale	(13,939)	(11,968)
Increase in accrued interest receivable	(5,422)	(1,449)
Decrease in prepaid expenses	2,243	838
Decrease in accrued interest payable	1,121	1,104
Capitalization of servicing rights	(4,404)	(5,993)
Valuation allowance on servicing rights	(12)	(29)
Loss on sales/valuations of assets, net	2,243	1,642
Net excess tax benefit from stock based compensation	672	1,121
Other, net	(1,979)	(5,637)
NET CASH PROVIDED BY OPERATING ACTIVITIES	167,073	129,857
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of time deposits in other financial institutions	(1,000)	0
Proceeds from the sale of securities available for sale	694,872	1,127,091
Proceeds from the redemption of time deposits in other financial institutions	8,767	12,171
Proceeds from the maturity of and principal paydowns on securities available for sale	172,702	161,827
Proceeds from the maturity of and principal paydowns on securities held to maturity	13,169	6,645
Proceeds from the maturity of and principal paydowns on time deposits in other financial institutions	5,829	24,931
Proceeds from the maturity of and principal paydowns on other investments	2,038	2,574
Purchase of securities available for sale	(940,607)	(1,299,492)
Purchase of other investments	(2,411)	(1,012)
Net (increase) decrease in loans	(13,737)	45,139
Purchase of bank owned life insurance policies	(2,000)	(2,000)
Proceeds from sale of mortgage servicing rights	0	5,137
Capital expenditures	(11,793)	(6,876)
Net cash and cash equivalents received in acquisitions	212,197	71,089
Proceeds from the sale of equipment	998	1,845
Proceeds on sale of OREO and other repossessed assets	3,128	7,578
NET CASH PROVIDED BY INVESTING ACTIVITIES	142,152	156,647
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in demand deposits	156,497	181,206
Net increase (decrease) in savings deposits	130,704	(179,721)
Net decrease in time deposit accounts	(122,795)	(8,582)
Proceeds on short-term revolving credit line	25,000	20,000
Repayments on short-term revolving credit line	(25,000)	(15,000)
Net decrease in short-term borrowings	(183,552)	(168,667)
Proceeds from short term FHLB advances	355,602	186,039
Repayments of short term FHLB advances	(365,602)	(191,405)
Proceeds from other borrowings	30,131	0
Repayments of other borrowings	(56,221)	(8,573)
Purchase of treasury stock	(97)	(440)
Proceeds from issuance of common stock	286	804
Dividends paid	(12,806)	(9,153)
NET CASH USED BY FINANCING ACTIVITIES	(67,853)	(193,492)
Net increase in cash and cash equivalents	241,372	93,012
Cash and cash equivalents at beginning of year	196,003	158,724
CASH AND CASH EQUIVALENTS AT END OF PERIOD	437,375	251,736
Supplemental disclosures:
Cash paid for income/franchise taxes	14,754	10,775
Cash paid for interest	34,725	23,034
Loans transferred to OREO	5,016	4,955
Transfer of premises from premises, furniture and equipment, net, to premises, furniture and equipment held for sale	3,415	0
Deposits transferred to held for sale	50,312	0
Loans transferred to held for sale	31,379	0
Purchases of securities available for sale, accrued, not settled	3,481	2,063
Sales of securities available for sale, accrued, not settled	0	125
Conversion of convertible debt to common stock	0	558
Conversion of Series D preferred stock to common stock	938	419
Stock consideration granted for acquisitions	$ 238,075	$ 175,196

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Series D Preferred Stock	Preferred Stock	Preferred StockSeries D Preferred Stock	Common Stock	Capital Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance at beginning of period at Dec. 31, 2016	$ 740,916		$ 1,357		$ 26,120	$ 328,376	$ 416,109	$ (31,046)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	71,628						61,600	10,028
Cash dividends declared:
Preferred	(45)						(45)
Common	(9,108)						(9,108)
Conversion of Series D preferred stock		$ (419)		$ (419)
Purchase of shares of common stock	(440)								(440)
Issuance of shares of common stock	175,564				3,826	171,298			440
Stock based compensation	3,588					3,588
Balance at end of period at Sep. 30, 2017	981,684		938		29,946	503,262	468,556	(21,018)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of unrealized net gain on equity securities	0						280	(280)
Balance at beginning of period at Dec. 31, 2017	991,457		938		29,953	503,709	481,331	(24,474)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	59,789						84,857	(25,068)
Cash dividends declared:
Preferred	(39)						(39)
Common	(12,767)						(12,767)
Conversion of Series D preferred stock		$ (938)		$ (938)
Purchase of shares of common stock	(97)								(97)
Issuance of shares of common stock	239,299				4,520	234,682			97
Stock based compensation	3,689					3,689
Balance at end of period at Sep. 30, 2018	$ 1,280,393		$ 0		$ 34,473	$ 742,080	$ 553,662	$ (49,822)	$ 0

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash dividends per share common stock (in dollars per share)	$ 0.40	$ 0.33
Shares of common stock purchased (in shares)	1,761	9,392
Shares of common stock issued (in shares)	4,521,434	3,835,532
Series D Preferred Stock
Cash dividends per share preferred stock (in dollars per share)	$ 52.50	$ 52.50

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION The interim unaudited consolidated financial statements contained herein should be read in conjunction with the audited consolidated financial statements and accompanying notes to the consolidated financial statements for the fiscal year ended December 31, 2017 , included in the Form 10-K of Heartland Financial USA, Inc. ("Heartland") filed with the Securities and Exchange Commission ("SEC") on February 28, 2018 . Foot note disclosures to the interim unaudited consolidated financial statements which would substantially duplicate the disclosure contained in the footnotes to the audited consolidated financial statements have been omitted. The financial information of Heartland included herein has been prepared in accordance with U.S. generally accepted accounting principles for interim financial reporting and has been prepared pursuant to the rules and regulations for reporting on Form 10-Q and Rule 10-01 of Regulation S-X. Such information reflects all adjustments (consisting of normal recurring adjustments), that are, in the opinion of management, necessary for a fair presentation of the financial position and results of operations for the periods presented. The results of the interim period ended September 30, 2018 , are not necessarily indicative of the results expected for the year ending December 31, 2018 . In the Annual Report on Form 10-K for the year ended December 31, 2017, Heartland reported the results of operations through two business segments: Community and Other Banking and Mortgage Banking. Effective January 1, 2018, the recently restructured mortgage banking segment is no longer a reportable segment due to the significant reduction in infrastructure and the reporting structure of the mortgage sales staff, who currently report directly to the bank president in each market. Accordingly, Heartland is no longer reporting results of operations by segment. Earnings Per Share Basic earnings per share is determined using net income available to common stockholders and weighted average common shares outstanding. Diluted earnings per share is computed by dividing net income available to common stockholders by the weighted average common shares and assumed incremental common shares issued. Amounts used in the determination of basic and diluted earnings per share for the three- and nine- month periods ended September 30, 2018 , and 2017 , are shown in the table below: Three Months Ended (Dollars and number of shares in thousands, except per share data) 2018 2017 Net income $ 33,710 $ 21,632 Preferred dividends (13 ) (13 ) Interest expense on convertible preferred debt — 3 Net income available to common stockholders $ 33,697 $ 21,622 Weighted average common shares outstanding for basic earnings per share 34,452 29,648 Assumed incremental common shares issued upon vesting of outstanding restricted stock units 192 262 Weighted average common shares for diluted earnings per share 34,644 29,910 Earnings per common share — basic $ 0.98 $ 0.73 Earnings per common share — diluted $ 0.97 $ 0.72 Number of antidilutive common stock equivalents excluded from diluted earnings per share computation — — Nine Months Ended (Dollars and number of shares in thousands, except per share data) 2018 2017 Net income $ 84,857 $ 61,600 Preferred dividends (39 ) (45 ) Interest expense on convertible preferred debt — 12 Net income available to common stockholders $ 84,818 $ 61,567 Weighted average common shares outstanding for basic earnings per share 32,520 27,569 Assumed incremental common shares issued upon vesting of outstanding restricted stock units 187 265 Weighted average common shares for diluted earnings per share 32,707 27,834 Earnings per common share — basic $ 2.61 $ 2.23 Earnings per common share — diluted $ 2.59 $ 2.21 Number of antidilutive common stock equivalents excluded from diluted earnings per share computation — — Stock-Based Compensation Heartland may grant, through its Nominating and Compensation Committee (the "Compensation Committee"), non-qualified and incentive stock options, stock appreciation rights, stock awards, restricted stock, restricted stock units and cash incentive awards, under its 2012 Long-Term Incentive Plan (the "Plan"). The Plan was originally approved by stockholders in May 2012 and was amended effective March 8, 2016, to increase the number of shares of common stock authorized for issuance and make certain other changes to the Plan. As of September 30, 2018 , 442,320 shares of common stock were available for issuance under future awards that may be granted under the Plan to employees and directors of, and service providers to, Heartland or its subsidiaries. Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 718, "Compensation-Stock Compensation" requires the measurement of the cost of employee services received in exchange for an award of equity instruments based upon the fair value of the award on the grant date. The cost of the award is based upon its fair value estimated on the date of grant and recognized in the consolidated statements of income over the vesting period of the award. The fair market value of restricted stock and restricted stock units is based on the fair value of the underlying shares of common stock on the date of grant. The fair value of stock options is estimated on the date of grant using the Black-Scholes model. Forfeitures are accounted for as they occur. The amount of tax benefit related to the exercise, vesting and forfeiture of equity-based awards reflected as a tax benefit in Heartland's income tax expense was $672,000 and $1.1 million during the nine months ended September 30, 2018 and 2017, respectively. Restricted Stock Units The Plan permits the Compensation Committee to grant restricted stock units ("RSUs"). In the first quarter of 2018, the Compensation Committee granted time-based RSUs with respect to 52,153 shares of common stock, and in the first quarter of 2017, the Compensation Committee granted time-based RSUs with respect to 55,665 shares of common stock to selected officers and employees. The time-based RSUs represent the right, without payment, to receive shares of Heartland common stock on a specified date in the future. The time-based RSUs granted in 2018 vest over three years in equal installments on March 6 of each of the three years following the year of the grant, while the 2017 time-based RSUs vest in equal installments on January 19 of each of the three years following the year of the grant. The time-based RSUs may also vest upon death or disability, upon a change in control or upon a "qualified retirement" (as defined in the RSU agreement). The retiree is required to sign a non-solicitation agreement as a condition to vesting. In addition to the time-based RSUs referenced in the preceding paragraph, the Compensation Committee granted one -year performance-based RSUs with respect to 18,988 shares of common stock in the first quarter of 2018, and 27,570 shares of common stock in the first quarter of 2017. These performance-based RSUs are earned based on satisfaction of performance targets for the fiscal years ended December 31, 2018, and December 31, 2017, respectively, and then fully vest on a specified date in the third calendar year following the year of the initial grant. The Compensation Committee also granted three -year performance-based RSUs with respect to 16,108 shares and 9,032 shares of common stock in the first quarter of 2018 and 2017, respectively. These performance-based RSUs will be earned based on satisfaction of performance targets for the three -year performance period ended December 31, 2020, and December 31, 2019, respectively. These performance-based RSUs or a portion thereof may vest in 2021 and 2020, respectively, after measurement of performance in relation to the performance targets. The one -year and three -year performance-based RSUs vest to the extent that they are earned upon death or disability or upon a "qualified retirement." Upon a change in control, performance-based RSUs shall become vested at 100% of target if the RSU obligations are not assumed by the successor company. If the successor company does assume the RSU obligations, the 2017 and 2018 performance-based RSUs will vest at 100% of target upon a "Termination of Service" within the period beginning six months prior to a change in control and ending twenty-four months after a change in control. All of Heartland's RSUs will be settled in common stock upon vesting and are not entitled to dividends until vested. The Compensation Committee may grant RSUs under the Plan to directors as part of their compensation, to new management level employees at commencement of employment, and to other employees and service providers as incentives. During the nine months ended September 30, 2018 , and September 30, 2017 , 29,048 and 16,804 time-based RSUs, respectively, were granted to directors and new employees. A summary of the RSUs outstanding as of September 30, 2018 , and 2017 , and changes during the nine months ended September 30, 2018 and 2017 , follows: 2018 2017 Shares Weighted-Average Grant Date Fair Value Shares Weighted-Average Grant Date Fair Value Outstanding at January 1 301,578 $ 34.74 346,817 $ 27.61 Granted 116,297 55.26 109,071 47.21 Vested (127,429 ) 32.70 (136,428 ) 26.66 Forfeited (27,678 ) 45.58 (12,923 ) 31.57 Outstanding at September 30 262,768 $ 43.65 306,537 $ 34.72 Total compensation costs recorded for RSUs were $3.7 million and $3.6 million for the nine -month periods ended September 30, 2018 and 2017 . As of September 30, 2018 , there were $5.3 million of total unrecognized compensation costs related to the Plan for RSUs that are expected to be recognized through 2021. Options Although the Plan provides authority to the Compensation Committee to grant stock options, no options were granted during the first nine months of 2018 and 2017 . Prior to 2009, options were typically granted annually with an expiration date ten years after the date of grant. Vesting was generally over a five -year service period with equal portions of a grant becoming exercisable at three years, four years, and five years after the date of grant. A summary of the stock options outstanding as of September 30, 2018 and 2017 , and changes during the nine months ended September 30, 2018 and 2017 , follows: 2018 2017 Shares Weighted-Average Exercise Price Shares Weighted-Average Exercise Price Outstanding at January 1 6,500 $ 18.60 26,400 $ 18.60 Granted — — — — Exercised (6,500 ) 18.60 (13,650 ) 18.60 Forfeited — — (500 ) 18.60 Outstanding at September 30 — $ — 12,250 $ 18.60 Options exercisable at September 30 — $ — 12,250 $ 18.60 The intrinsic value for the total of all options exercised during the nine months ended September 30, 2018 , was $231,000 . Cash received from options exercised was $ 121,000 for the nine months ended September 30, 2018 , and $254,000 for the nine months ended September 30, 2017 . No compensation costs were recorded for options during the nine month periods ended September 30, 2018 and 2017 . There are no unrecorded compensation costs related to options at September 30, 2018 . No stock options vested during the nine -month periods ended September 30, 2018 and 2017 . Subsequent Events - Heartland has evaluated subsequent events that may require recognition or disclosure through the filing date of this Quarterly Report on Form 10-Q with the SEC. Effect of New Financial Accounting Standards In May 2014, the FASB issued Accounting Standards Update ("ASU") 2014-09, " Revenue from Contracts with Customers." The amendment clarifies the principles for recognizing revenue and develops a common revenue standard. The amendment outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that "an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services." In applying the revenue model to contracts within its scope, an entity should apply the following steps: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The new guidance does not apply to certain contracts within the scope of other ASC Topics, such as lease contracts, insurance contracts, financing arrangements, financial instruments, guarantees other than product or service warranties and nonmonetary exchanges between entities in the same line of business to facilitate sales to customers. Heartland evaluates noninterest income contracts affected by the new guidance by analyzing contracts and current accounting practices to determine if a change is appropriate. The amendment is largely consistent with existing guidance and current practices. Heartland adopted the accounting standard effective January 1, 2018, as required, using a modified retrospective approach. However, the adoption of these amendments did not have a significant effect on Heartland's results of operations, financial position and liquidity other than expanded disclosure requirements. See Note 9, "Revenue," for further details regarding Heartland's revenue streams subject to the accounting standard. In January 2016, the FASB issued guidance ASU 2016-01, " Recognition and Measurement of Financial Assets and Financial Liabilitie s." The amendments in ASU 2016-01 to Subtopic 825-10, Financial Instruments, contain the following elements: (1) require equity investments to be measured at fair value with changes in fair value recognized in net income; (2) simplify the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (3) eliminate the requirement for public entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; (4) require public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (5) require an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (6) require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or accompanying notes to the financial statements; and (7) clarify that the entity should evaluate the need for a valuation allowance on a deferred tax asset related to available for sale securities in combination with the entity's other deferred tax assets. The amendments are effective for fiscal years beginning after December 15, 2017, and for interim periods within those fiscal years. Except for the early application of the amendment noted in item (5) above, early adoption of the amendments in this update is not permitted. Entities are required to and Heartland applied the amendment by means of a cumulative-effect adjustment as of the beginning of the fiscal year of adoption, with the exception of the amendment related to equity securities without readily determinable fair values, which is to be applied prospectively to equity investments that exist as of the adoption date. Heartland adopted the accounting standard on January 1, 2018, as required, and the adoption of these amendments did not have a material impact on its results of operations, financial position and liquidity. Heartland reclassified $280,000 from accumulated other comprehensive income to retained earnings on January 1, 2018, related to the fair value of its equity investments. In February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842). " Topic 842 requires a lessee to recognize leases on-balance sheet and disclose key information about leasing arrangements. The new standard establishes a right-of-use model (ROU) that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. Leases will be classified as financing or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The amendment is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and will be applied on a modified retrospective basis. Heartland leases certain properties and equipment under operating leases that will result in recognition of lease assets and lease liabilities on the consolidated balance sheets under the ASU; however the majority of Heartland's properties and equipment are owned, not leased. The modified retrospective approach includes a number of optional practical expedients that entities may elect to apply. These practical expedients relate to the identification and classification of leases that commenced before the effective date, initial direct costs for leases that commenced before the effective date, and the ability to use hindsight in evaluating lessee options to extend or terminate a lease or to purchase the underlying asset. Early adoption is permitted. In January 2018, the FASB issued an amendment to provide entities with the optional practical expedient to not evaluate existing or expired land easements that were previously not accounted for as leases under Topic 840. In July 2018, the FASB issued ASU 2018-11, " Leases - Targeted Improvements " to provide entities with relief from the costs of implementing certain aspects of the new leasing standard, Specifically, under the amendments in ASU 2018-11, entities may elect not to recast the comparative periods presented when transitioning to the new leasing standard, and lessors may elect not to separate lease and non-lease components when certain conditions are met. The amendments have the same effective date as ASU 2016-02. Heartland intends to adopt the accounting standard on January 1, 2019, as required, and will not restate comparative periods. Heartland also expects to adopt certain optional practical expedients. Heartland signed an agreement with a cloud-based lease software provider, and the software implementation is nearly complete. Based on Heartland's current lease portfolio, management anticipates recognizing a right-of-use asset and lease liability on the consolidated balance sheet, with an immaterial impact to the consolidated statement of income. However, the ultimate impact of the standard will depend on the lease portfolio on January 1, 2019. In June 2016, the FASB issued ASU 2016-13, " Financial Instruments - Credit Losses (Topic 326) ." The amendments in this ASU, also referred to as "CECL," require a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. The amendments in this ASU indicate that an entity should not use the length of time a security has been in an unrealized loss position to avoid recording a credit loss. In addition, in determining whether a credit loss exists, the amendments in this ASU also remove the requirements to consider the historical and implied volatility of the fair value of a security and recoveries or declines in fair value after the balance sheet date. The amendment is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. An entity may adopt the amendments earlier as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Heartland intends to adopt the accounting standard in 2020, as required, and expects to recognize a one-time cumulative effect adjustment to the allowance for loan losses as of the beginning of the first reporting period in which the new standard is effective, but cannot yet determine the magnitude of any such one-time adjustment or the overall impact of the new guidance on the results of operations, financial position and liquidity. Heartland has formed a cross-functional internal committee to assess and implement the standard, and the project plan calls for running a parallel CECL model during 2019 prior to adoption in 2020. Heartland has entered into an agreement with a third party software vendor, selected CECL-compliant methodologies, and started implementation of the software. In August 2016, the FASB issued ASU 2016-15, " Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. " The amendments in this update address eight specific cash flow issues with the objective of reducing the existing diversity in practice. The amendment is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes the interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The amendments in this update should be applied using a retrospective transition method to each period presented. Heartland adopted this ASU on January 1, 2018, as required, and the adoption of these amendments did not have a material impact on Heartland's results of operations, financial position and liquidity. In October 2016, the FASB issued ASU 2016-16, "Income Taxes (Topic 740) - Intra-Entity Transfer of Assets Other Than Inventory." The amendment requires an entity to recognize income tax consequences on an intra-entity transfer of an asset other than inventory at the time the transaction occurs. The amendment is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The amendments must be applied and Heartland applied these amendments using a modified retrospective basis. Heartland adopted this ASU on January 1, 2018, as required, and the adoption of this amendment did not have a material impact on Heartland's results of operations, financial position and liquidity. In January 2017, the FASB issued ASU No. 2017-01, " Business Combinations (Topic 805): Clarifying the Definition of a Business ," which narrows the definition of a business and provides a framework that gives entities a basis for making reasonable judgments about whether a transaction involves an asset or a business. ASU 2017-01 is effective for public business entities in annual periods beginning after December 15, 2017, including interim periods therein. Heartland adopted ASU 2017-01 on January 1, 2018, as required, and the adoption did not have a material impact on Heartland's results of operations, financial position, and liquidity. In January 2017, the FASB issued ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350)." This amendment is to simplify the subsequent measurement of goodwill by eliminating step two from the goodwill impairment test. Instead, an entity will perform only step one of its quantitative goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and then recognizing the impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value; however, the loss recognized cannot exceed the total amount of goodwill allocated to that reporting unit. An entity will still have the option to perform a qualitative assessment for a reporting unit to determine if the quantitative step one impairment test is necessary. This amendment is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied prospectively. Early adoption is permitted, including in an interim period for impairment tests performed after January 1, 2017. Heartland intends to adopt this ASU in the third quarter of 2020, consistent with the annual impairment test as of September 30, 2020, and is currently evaluating the potential impact of this guidance on its results of operations, financial position and liquidity. In March 2017, the FASB issued ASU 2017-08, "Receivables - Nonrefundable Fee and Other Costs (Subtopic 310-20)." These amendments shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount. Discounts continue to be amortized to maturity. These amendments are effective for public business entities for fiscal years and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. If any entity early adopts the amendments in an interim period, any adjustments must be reflected as of the beginning of the fiscal year that includes the interim period. The amendments must be applied and Heartland intends to apply these amendments on a modified retrospective basis, with a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Heartland intends to adopt this ASU in 2019, as required, and is currently evaluating the potential impact on its results of operations, financial position and liquidity. In May 2017, the FASB issued ASU 2017-09, " Compensation - Stock Compensation (Topic 718) ." The amendments provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and (3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments are effective for annual periods and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim periods for public business entities for reporting periods for which financial statements have not yet been issued. The amendments should be applied and Heartland applied these amendments prospectively to an award modified on or after the adoption date. Heartland adopted this ASU on January 1, 2018, as required, and the adoption did not have a material impact to its results of operations, financial position and liquidity because Heartland has not typically modified share-based payment awards after the original award has been granted. In August 2017, the FASB issued ASU 2017-12, " Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities ." The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. ASU 2017-12 requires a modified retrospective transition method in which Heartland will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the consolidated balance sheet as of the date of adoption. Heartland intends to adopt this ASU in 2019, as required, and does not believe there will be a material impact to its results of operations, financial position and liquidity. In February 2018, the FASB issued ASU 2018-02, " Income Statement-Reporting Comprehensive Income (Topic 220). " This ASU allows for the option to reclassify from accumulated other comprehensive income ("AOCI") to retained earnings for stranded tax effects resulting from the newly enacted federal corporate income tax rate in the Tax Cuts and Jobs Act of 2017, which was enacted on December 22, 2017. The legislation included a reduction to the corporate income tax rate from 35 percent to 21 percent effective January 1, 2018. The amount of the reclassification would be the difference between the historical corporate income tax rate and the newly enacted 21 percent corporate income tax rate. The amendments in this ASU are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted for public businesses for reporting periods for which financial statements have not yet been issued. Heartland adopted the guidance as of December 31, 2017. The adoption of this ASU was accounted for as a cumulative-effect adjustment to the balance sheet resulting in a $4.5 million increase to retained earnings and a corresponding decrease to AOCI on December 31, 2017. In August 2018, the FASB issued ASU 2018-13, " Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. " This ASU eliminates, adds and modifies certain disclosure requirements for fair value measurements. Among the changes, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy but will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. ASU 2018-13 is effective for interim and annual reporting periods beginning after December 15, 2019, and early adoption is permitted. Heartland intends to adopt this ASU in 2020, as required, and because the ASU only revises disclosure requirements, the adoption of this ASU will not have a material impact on results of operations, financial position and liquidity.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS First Bank Lubbock Bancshares, Inc. On May 18, 2018, Heartland completed the acquisition of Lubbock, Texas based First Bank Lubbock Bancshares, Inc. ("FBLB"), parent company of First Bank & Trust, and PrimeWest Mortgage Corporation, which is a wholly-owned subsidiary of First Bank & Trust. Under the terms of the definitive merger agreement, Heartland acquired FBLB in a transaction valued at approximately $189.9 million , of which $ 5.5 million was cash, and the remainder was settled by delivery of 3,350,664 shares of Heartland common stock. On the closing date, in addition to this merger consideration, Heartland provided FBLB the funds necessary to repay outstanding debt of $3.9 million , and Heartland assumed $8.2 million of trust preferred securities at fair value. Immediately after the close of the transaction, Heartland paid $13.3 million to the holders of FBLB's stock appreciation rights. The transaction included, at fair value, total assets of $1.12 billion , including $681.1 million of gross loans held to maturity, and deposits of $893.8 million . Upon closing of the transaction, First Bank & Trust became a wholly-owned subsidiary of Heartland and continues to operate under its current name and management team as Heartland's eleventh state-chartered bank. The transaction was a tax-free reorganization with respect to the stock consideration received by the stockholders of FBLB. The assets and liabilities of FBLB were recorded on the consolidated balance sheet at the estimated fair value on the acquisition date. The following table represents, in thousands, the amounts recorded on the consolidated balance sheet as of May 18, 2018: As of May 18, 2018 Fair value of consideration paid: Common stock (3,350,664 shares) $ 184,454 Cash 5,451 Total consideration paid 189,905 Fair value of assets acquired Cash and cash equivalents 212,105 Securities: Carried at fair value 1,788 Other securities 3,268 Loans held for sale 31,050 Loans held to maturity 681,080 Premises, furniture and equipment, net 23,271 Other real estate, net 379 Mortgage servicing rights 6,995 Core deposit intangibles and customer relationships, net 13,908 Cash surrender value on life insurance 14,997 Other assets 7,185 Total assets 996,026 Fair value of liabilities assumed Deposits 893,827 Other borrowings 12,077 Other liabilities 21,580 Total liabilities assumed 927,484 Fair value of net assets acquired 68,542 Goodwill resulting from acquisition $ 121,363 Heartland recognized $121.4 million of goodwill in conjunction with the acquisition of FBLB, which is calculated as the excess of both the consideration exchanged and the liabilities assumed as compared to the fair value of identifiable assets acquired. Goodwill resulted from the expected operational synergies, enhanced market area, cross-selling opportunities and expanded business lines. See Note 6 for further information on goodwill. Pro Forma Information (unaudited): The following pro forma information represents the results of operations for the nine-month periods ended September 30, 2018, and 2017, as if the FBLB acquisition occurred on January 1, 2018, and January 1, 2017, respectively: (Dollars in thousands, except per share data), unaudited For the Nine Months Ended September 30, 2018 September 30, 2017 Net interest income $ 317,846 $ 262,367 Net income available to common stockholders $ 69,075 $ 76,698 Basic earnings per share $ 2.02 $ 2.48 Diluted earnings per share $ 2.01 $ 2.46 The above pro forma results are presented for illustrative purposes and are not intended to represent or be indicative of the actual results of operations of the merged companies that would have been achieved had the acquisition occurred on January 1, 2018, and January 1, 2017, respectively, nor are they intended to represent or be indicative of future results of operations. The pro forma results do not include expected operating cost savings as a result of the acquisition or adjustments for $6.0 million of transaction costs or $13.3 million of stock appreciation rights expense recorded by FBLB in 2018 prior to the acquisition. The pro forma results also do not include adjustment for income taxes. These pro forma results require significant estimates and judgments particularly with respect to valuation and accretion of income associated with the acquired loans. Heartland incurred $1.1 million of pre-tax merger related expenses in the nine months ended September 30, 2018, associated with the FBLB acquisition. The merger expenses are reflected on the consolidated statements of income for the applicable period and are reported primarily in the categories of professional fees and other noninterest expenses. Acquired loans were preliminarily recorded at fair value based on a discounted cash flow valuation methodology that considers, among other things, projected default rates, loss given defaults and recovery rates. No allowance for credit losses was carried over from the acquisition. The balance of nonaccrual loans on the acquisition date was $7.6 million . Signature Bancshares, Inc. On February 23, 2018, Heartland completed the acquisition of Signature Bancshares, Inc., parent company of Signature Bank, headquartered in Minnetonka, Minnesota. Under the terms of the definitive merger agreement, Heartland acquired Signature Bancshares, Inc. in a transaction valued at approximately $61.4 million , of which $7.8 million was cash, and the remainder was settled by delivery of 1,000,843 shares of Heartland common stock. Simultaneous with the close, Signature Bank merged into Heartland's wholly-owned Minnesota Bank & Trust subsidiary, and the combined entity operates under the Minnesota Bank & Trust brand name. The transaction included, at fair value, total assets of $427.1 million , including $324.5 million of gross loans held to maturity, and deposits of $357.3 million . On the closing date, Heartland provided Signature Bancshares, Inc. the funds necessary to repay outstanding subordinated debt of $5.9 million . The transaction was a tax-free reorganization with respect to the stock consideration received by the stockholders of Signature Bancshares, Inc. Citywide Banks of Colorado, Inc. On July 7, 2017, Heartland acquired Citywide Banks of Colorado, Inc., parent company of Citywide Banks, headquartered in Aurora, Colorado. The transaction consideration was approximately $211.2 million , of which $58.6 million was cash, and the remainder was settled by delivery of 3,216,161 shares of Heartland common stock. Simultaneous with the close, Citywide Banks merged into Heartland's Centennial Bank and Trust subsidiary, and the combined entity operates as Citywide Banks. The transaction included, at fair value, total assets of $1.49 billion , including $985.4 million of net loans outstanding, and $1.21 billion of deposits on the acquisition date. Included in this transaction was one bank building with a fair value of $1.4 million that Heartland intends to sell and is classified as premises, furniture and equipment held for sale on the consolidated balance sheets. The transaction was a tax-free reorganization with respect to the stock consideration received by the stockholders of Citywide Banks of Colorado, Inc. Founders Bancorp On February 28, 2017, Heartland acquired Founders Bancorp, parent company of Founders Community Bank, based in San Luis Obispo, California. The purchase price was approximately $31.0 million , which was paid by delivery of 455,877 shares of Heartland common stock and cash of $8.4 million . The transaction included, at fair value, total assets of $213.9 million , loans of $96.4 million , and deposits of $181.5 million on the acquisition date. The transaction also included one bank building with a fair value of $576,000 that Heartland sold during the second quarter of 2017. Simultaneous with the closing of the transaction, Founders Community Bank merged into Heartland's Premier Valley Bank subsidiary. The transaction was a tax-free reorganization with respect to the stock consideration received by the stockholders of Founders Bancorp.

Securities

Securities	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	SECURITIES The amortized cost, gross unrealized gains and losses, and estimated fair values of debt securities available for sale and equity securities with a readily determinable that are carried at fair value as of September 30, 2018 , and December 31, 2017 , are summarized in the table below, in thousands: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value September 30, 2018 U.S. government corporations and agencies $ 27,112 $ — $ (115 ) $ 26,997 Mortgage and asset-backed securities 1,926,803 1,341 (56,325 ) 1,871,819 Obligations of states and political subdivisions 372,146 239 (13,902 ) 358,483 Total debt securities 2,326,061 1,580 (70,342 ) 2,257,299 Equity securities with a readily determinable fair value 16,916 — — 16,916 Total $ 2,342,977 $ 1,580 $ (70,342 ) $ 2,274,215 December 31, 2017 U.S. government corporations and agencies $ 5,358 $ 8 $ (38 ) $ 5,328 Mortgage and asset-backed securities 1,785,467 5,856 (37,587 ) 1,753,736 Obligations of states and political subdivisions 441,060 4,669 (4,714 ) 441,015 Total debt securities 2,231,885 10,533 (42,339 ) 2,200,079 Equity securities 16,296 378 — 16,674 Total $ 2,248,181 $ 10,911 $ (42,339 ) $ 2,216,753 Investment securities as shown in this report reflect categories as required by Heartland’s adoption of ASU 2016-01, "Recognition and Measurement of Financial Assets and Financial Liabilities", on January 1, 2018. That new guidance refined the definition of equity securities and required their segregation from available for sale debt securities. While changes in the fair value of available for sale debt securities continue to be recorded in the equity category of accumulated other comprehensive income, the new guidance requires changes in the fair value of equity securities to be recorded in current earnings. As required by the new guidance, the unrealized gain in fair value on equity securities (recorded in accumulated other comprehensive income at December 31, 2017) was reclassified to retained earnings on January 1, 2018. The amount of the reclassification was $280,000 , net of tax. Equity securities include money market accounts that totaled $16.9 million at cost and $ 16.9 million at fair value at September 30, 2018 . The portion of unrealized net gains on equity securities recognized in current earnings during the first nine months of 2018, which related to securities still held at September 30, 2018 , totaled $97,000 . The amortized cost, gross unrealized gains and losses and estimated fair values of held to maturity securities as of September 30, 2018 , and December 31, 2017 , are summarized in the table below, in thousands: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value September 30, 2018 Obligations of states and political subdivisions $ 239,908 $ 8,422 $ (936 ) $ 247,394 Total $ 239,908 $ 8,422 $ (936 ) $ 247,394 December 31, 2017 Obligations of states and political subdivisions $ 253,550 $ 12,460 $ (516 ) $ 265,494 Total $ 253,550 $ 12,460 $ (516 ) $ 265,494 At September 30, 2018 , approximately 70% of Heartland's mortgage and asset-backed securities were issued by government-sponsored enterprises. The amortized cost and estimated fair value of investment securities carried at fair value at September 30, 2018 , by contractual maturity, are as follows, in thousands. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without penalties. September 30, 2018 Amortized Cost Estimated Fair Value Due in 1 year or less $ 23,216 $ 23,161 Due in 1 to 5 years 50,520 49,592 Due in 5 to 10 years 131,431 125,824 Due after 10 years 194,091 186,903 Total debt securities 399,258 385,480 Mortgage and asset-backed securities 1,926,803 1,871,819 Equity securities with a readily determinable fair value 16,916 16,916 Total investment securities $ 2,342,977 $ 2,274,215 The amortized cost and estimated fair value of debt securities held to maturity at September 30, 2018 , by contractual maturity, are as follows, in thousands. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without penalties. September 30, 2018 Amortized Cost Estimated Fair Value Due in 1 year or less $ 1,274 $ 1,281 Due in 1 to 5 years 31,121 31,495 Due in 5 to 10 years 105,183 107,052 Due after 10 years 102,330 107,566 Total investment securities $ 239,908 $ 247,394 As of September 30, 2018 , and December 31, 2017 , securities with a fair value of $551.3 million and $670.3 million , respectively, were pledged to secure public and trust deposits, short-term borrowings and for other purposes as required or permitted by law. Gross gains and losses realized related to the sales of securities carried at fair value for the three- and nine- month periods ended September 30, 2018 and 2017 , are summarized as follows, in thousands: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Proceeds from sales $ 59,137 $ 503,083 $ 694,872 $ 1,127,091 Gross security gains 67 2,088 3,537 8,585 Gross security losses 212 409 2,500 3,023 The following tables summarize, in thousands, the amount of unrealized losses, defined as the amount by which cost or amortized cost exceeds fair value, and the related fair value of investments with unrealized losses in Heartland's securities portfolio as of September 30, 2018 , and December 31, 2017 . The investments were segregated into two categories: those that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 months or more. The reference point for determining how long an investment was in an unrealized loss position w as September 30, 2017 , and December 31, 2016 , respectively. Securities for which Heartland has taken credit-related other-than-temporary impairment ("OTTI") write-downs are categorized as being "less than 12 months" or "12 months or longer" in a continuous loss position based on the point in time that the fair value declined to below the cost basis and not the period of time since the credit-related OTTI write-down. Debt securities available for sale Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses September 30, 2018 U.S. government corporations and agencies $ 22,392 $ (39 ) $ 4,605 $ (76 ) $ 26,997 $ (115 ) Mortgage and asset-backed securities 1,007,078 (18,299 ) 668,623 (38,026 ) 1,675,701 (56,325 ) Obligations of states and political subdivisions 203,363 (5,552 ) 139,394 (8,350 ) 342,757 (13,902 ) Total temporarily impaired securities $ 1,232,833 $ (23,890 ) $ 812,622 $ (46,452 ) $ 2,045,455 $ (70,342 ) December 31, 2017 U.S. government corporations and agencies $ 4,819 $ (38 ) $ — $ — $ 4,819 $ (38 ) Mortgage and asset-backed securities 851,070 (11,533 ) 399,978 (26,054 ) 1,251,048 (37,587 ) Obligations of states and political subdivisions 93,040 (667 ) 159,180 (4,047 ) 252,220 (4,714 ) Total temporarily impaired securities $ 948,929 $ (12,238 ) $ 559,158 $ (30,101 ) $ 1,508,087 $ (42,339 ) Securities held to maturity Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses September 30, 2018 Obligations of states and political subdivisions $ 29,174 $ (209 ) $ 13,160 $ (727 ) $ 42,334 $ (936 ) Total temporarily impaired securities $ 29,174 $ (209 ) $ 13,160 $ (727 ) $ 42,334 $ (936 ) December 31, 2017 Obligations of states and political subdivisions $ 8,512 $ (49 ) $ 8,989 $ (467 ) $ 17,501 $ (516 ) Total temporarily impaired securities $ 8,512 $ (49 ) $ 8,989 $ (467 ) $ 17,501 $ (516 ) Heartland reviews the investment securities portfolio on a quarterly basis to monitor its exposure to OTTI. A determination as to whether a security's decline in fair value is other-than-temporary takes into consideration numerous factors and the relative significance of any single factor can vary by security. Some factors Heartland may consider in the OTTI analysis include the length of time the security has been in an unrealized loss position, changes in security ratings, financial condition of the issuer, as well as security and industry specific economic conditions. In addition, with regard to debt securities, Heartland may also evaluate payment structure, whether there are defaulted payments or expected defaults, prepayment speeds and the value of any underlying collateral. For certain debt securities in unrealized loss positions, Heartland prepares cash flow analyses to compare the present value of cash flows expected to be collected from the security with the amortized cost basis of the security. The remaining unrealized losses on Heartland's mortgage and asset-backed securities are the result of changes in market interest rates or widening of market spreads subsequent to the initial purchase of the securities. The losses are not related to concerns regarding the underlying credit of the issuers or the underlying collateral. It is expected that the securities will not be settled at a price less than the amortized cost of the investment. Because the decline in fair value is attributable to changes in interest rates or widening market spreads and not credit quality, and because Heartland has the intent and ability to hold these investments until a market price recovery or to maturity and does not believe it will be required to sell the securities before maturity, these investments are not considered other-than-temporarily impaired. The remaining unrealized losses on Heartland's obligations of states and political subdivisions are the result of changes in market interest rates or widening of market spreads subsequent to the initial purchase of the securities. Management monitors the published credit ratings of these securities and the stability of the underlying municipalities. Because the decline in fair value is attributable to changes in interest rates or widening market spreads due to insurance company downgrades and not underlying credit quality, and because Heartland has the intent and ability to hold these investments until a market price recovery or to maturity and does not believe it will be required to sell the securities before maturity, these investments are not considered other-than-temporarily impaired. There were no gross realized gains or losses on the sale of securities carried at fair value or held to maturity securities with OTTI write-downs for the nine -month periods ended September 30, 2018 , and September 30, 2017 , respectively. Other investments, at cost, include equity securities without a readily determinable fair value. Equity securities without a readily determinable fair value totaled $22.4 million and $18.6 million at September 30, 2018 , and December 31, 2017, respectively. At September 30, 2018 , and December 31, 2017 , other investments at cost included shares of stock in the Federal Home Loan Banks (the "FHLBs") of Des Moines, Chicago, Dallas, San Francisco and Topeka at an amortized cost of $15.1 million and $ 14.0 million , respectively. The Heartland banks are required by federal law to maintain FHLB stock as members of the various FHLBs. These equity securities are "restricted" in that they can only be sold back to the respective institutions from which they were acquired or another member institution at par. Therefore, the FHLB stock is less liquid than other marketable equity securities, and the fair value approximates amortized cost. Heartland considers its FHLB stock as a long-term investment that provides access to competitive products and liquidity. Heartland evaluates impairment in these investments based on the ultimate recoverability of the par value and, at September 30, 2018 , did not consider the investments to be other than temporarily impaired.

Loans

Loans	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans	LOANS Loans as of September 30, 2018 , and December 31, 2017 , were as follows, in thousands: September 30, 2018 December 31, 2017 Loans receivable held to maturity: Commercial $ 1,962,222 $ 1,646,606 Commercial real estate 3,648,731 3,163,269 Agricultural and agricultural real estate 574,048 511,588 Residential real estate 676,941 624,279 Consumer 506,181 447,484 Gross loans receivable held to maturity 7,368,123 6,393,226 Unearned discount (1,340 ) (556 ) Deferred loan fees (1,290 ) (1,206 ) Total net loans receivable held to maturity 7,365,493 6,391,464 Allowance for loan losses (61,221 ) (55,686 ) Loans receivable, net $ 7,304,272 $ 6,335,778 Heartland has certain lending policies and procedures in place that are designed to provide for an acceptable level of credit risk. The board of directors reviews and approves these policies and procedures on a regular basis. A reporting system supplements the review process by providing management and the board with frequent reports related to loan production, loan quality, concentrations of credit, loan delinquencies and nonperforming loans and potential problem loans. Diversification in the loan portfolio is also a means of managing risk associated with fluctuations in economic conditions. Heartland originates commercial and commercial real estate loans for a wide variety of business purposes, including lines of credit for capital and operating purposes and term loans for real estate and equipment purchases. Agricultural loans provide financing for capital improvements and farm operations, as well as livestock and machinery purchases. Residential mortgage loans are originated for the construction, purchase or refinancing of single family residential properties. Consumer loans include loans for motor vehicles, home improvement, home equity and personal lines of credit. Heartland's consumer finance subsidiaries, Citizens Finance Co. and Citizens Finance of Illinois Co., typically lend to borrowers with past credit problems or limited credit histories, which comprises approximately 14% of Heartland's total consumer loan portfolio. Under Heartland’s credit practices, a loan is impaired when, based on current information and events, it is probable that Heartland will be unable to collect all amounts due according to the contractual terms of the loan agreement. Loan impairment is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, except where more practical, impairment is measured at the observable market price of the loan or the fair value of the collateral if the loan is collateral dependent. The following table shows the balance in the allowance for loan losses at September 30, 2018 , and December 31, 2017 , and the related loan balances, disaggregated on the basis of impairment methodology, in thousands. Loans evaluated under ASC 310-10-35 include loans on nonaccrual status and troubled debt restructurings, which are individually evaluated for impairment, and other impaired loans deemed to have similar risk characteristics. All other loans are collectively evaluated for impairment under ASC 450-20. Heartland has made no significant changes to the accounting for the allowance for loan losses during 2018. Allowance For Loan Losses Gross Loans Receivable Held to Maturity Ending Balance Under ASC 310-10-35 Ending Balance Under ASC 450-20 Total Ending Balance Evaluated for Impairment Under ASC 310-10-35 Ending Balance Evaluated for Impairment Under ASC 450-20 Total September 30, 2018 Commercial $ 4,165 $ 17,904 $ 22,069 $ 23,414 $ 1,938,808 $ 1,962,222 Commercial real estate 214 23,476 23,690 14,415 3,634,316 3,648,731 Agricultural and agricultural real estate 260 4,306 4,566 17,522 556,526 574,048 Residential real estate 279 1,571 1,850 23,647 653,294 676,941 Consumer 1,085 7,961 9,046 8,671 497,510 506,181 Total $ 6,003 $ 55,218 $ 61,221 $ 87,669 $ 7,280,454 $ 7,368,123 December 31, 2017 Commercial $ 1,613 $ 16,485 $ 18,098 $ 7,415 $ 1,639,191 $ 1,646,606 Commercial real estate 766 21,184 21,950 23,705 3,139,564 3,163,269 Agricultural and agricultural real estate 546 3,712 4,258 13,304 498,284 511,588 Residential real estate 430 1,794 2,224 27,141 597,138 624,279 Consumer 1,400 7,756 9,156 6,903 440,581 447,484 Total $ 4,755 $ 50,931 $ 55,686 $ 78,468 $ 6,314,758 $ 6,393,226 The following table presents nonaccrual loans, accruing loans past due 90 days or more and performing troubled debt restructured loans at September 30, 2018 , and December 31, 2017 , in thousands: September 30, 2018 December 31, 2017 Nonaccrual loans $ 68,528 $ 58,272 Nonaccrual troubled debt restructured loans 4,532 4,309 Total nonaccrual loans $ 73,060 $ 62,581 Accruing loans past due 90 days or more $ 154 $ 830 Performing troubled debt restructured loans $ 4,180 $ 6,617 The following tables provide information on troubled debt restructured loans that were modified during the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , dollars in thousands: Three Months Ended 2018 2017 Number Pre- Post- Number Pre- Post- Commercial — $ — $ — — $ — $ — Commercial real estate — — — — — — Total commercial and commercial real estate — — — — — — Agricultural and agricultural real estate — — — — — — Residential real estate 1 92 94 8 1,174 1,174 Consumer — — — — — — Total 1 $ 92 $ 94 8 $ 1,174 $ 1,174 Nine Months Ended 2018 2017 Number of Loans Pre- Modification Recorded Investment Post- Modification Recorded Investment Number of Loans Pre- Modification Recorded Investment Post- Modification Recorded Investment Commercial — $ — $ — 3 $ 131 $ 131 Commercial real estate — — — — — — Total commercial and commercial real estate — — — 3 131 131 Agricultural and agricultural real estate — — — — — — Residential real estate 11 2,098 1,808 22 2,977 2,977 Consumer — — — — — — Total 11 $ 2,098 $ 1,808 25 $ 3,108 $ 3,108 The pre-modification and post-modification recorded investment represents amounts as of the date of loan modification. The change related to the pre-modification investment and post-modification investment amounts on Heartland's residential real estate trouble debt restructured loans for the nine -months ended September 30, 2018 , is due to $356,000 of principal deferment collected from government guarantees and $66,000 of capitalized interest and escrow. At September 30, 2018 , there were no commitments to extend credit to any of the borrowers with an existing troubled debt restructured loan. The following table shows troubled debt restructured loans for which there was a payment default during the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , that had been modified during the twelve-month period prior to default, in thousands: With Payment Defaults During the Three Months Ended September 30, 2018 2017 Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial — $ — — $ — Commercial real estate — — — — Total commercial and commercial real estate — — — — Agricultural and agricultural real estate — — — — Residential real estate 4 418 5 1,221 Consumer — — — — Total 4 $ 418 5 $ 1,221 With Payment Defaults During the Nine Months Ended September 30, 2018 2017 Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial — $ — — $ — Commercial real estate — — — — Total commercial and commercial real estate — — — — Agricultural and agricultural real estate — — — — Residential real estate 10 1,598 8 1,480 Consumer — — — — Total 10 $ 1,598 8 $ 1,480 Heartland's internal rating system is a series of grades reflecting management's risk assessment, based on its analysis of the borrower's financial condition. The "pass" category consists of all loans that are not in the "nonpass" category, categorized into a range of loan grades that reflect increasing, though still acceptable, risk. Movement of risk through the various grade levels in the pass category is monitored for early identification of credit deterioration. The "nonpass" category consists of special mention, substandard, doubtful and loss loans. The "special mention" rating is attached to loans where the borrower exhibits negative trends in financial circumstances due to borrower specific or systemic conditions that, if left uncorrected, threaten the borrower's capacity to meet its debt obligations. The borrower is believed to have sufficient financial flexibility to react to and resolve its negative financial situation. These credits are closely monitored for improvement or deterioration. The "substandard" rating is assigned to loans that are inadequately protected by the current net worth and paying capacity of the borrower and that may be further at risk due to deterioration in the value of collateral pledged. Well-defined weaknesses jeopardize liquidation of the debt. These loans are still considered collectible; however, a distinct possibility exists that Heartland will sustain some loss if deficiencies are not corrected. Substandard loans may exhibit some or all of the following weaknesses: deteriorating financial trends, lack of earnings, inadequate debt service capacity, excessive debt and/or lack of liquidity. The "doubtful" rating is assigned to loans where identified weaknesses in the borrowers' ability to repay the loan make collection or liquidation in full, on the basis of existing facts, conditions and values, highly questionable and improbable. These borrowers are usually in default, lack liquidity and capital, as well as resources necessary to remain as an operating entity. Specific pending events, such as capital injections, liquidations or perfection of liens on additional collateral, may strengthen the credit, thus deferring the rating of the loan as "loss" until the exact status of the loan can be determined. The loss rating is assigned to loans considered uncollectible. Heartland had no loans classified as loss or doubtful as of September 30, 2018 . Loans are placed on "nonaccrual" when management does not expect to collect payments of principal and interest in full or when principal or interest has been in default for a period of 90 days or more, unless the loan is both well secured and in the process of collection. The following table presents loans by credit quality indicator at September 30, 2018 , and December 31, 2017 , in thousands: Pass Nonpass Total September 30, 2018 Commercial $ 1,825,692 $ 136,530 $ 1,962,222 Commercial real estate 3,467,522 181,209 3,648,731 Total commercial and commercial real estate 5,293,214 317,739 5,610,953 Agricultural and agricultural real estate 476,261 97,787 574,048 Residential real estate 644,592 32,349 676,941 Consumer 491,092 15,089 506,181 Total gross loans receivable held to maturity $ 6,905,159 $ 462,964 $ 7,368,123 December 31, 2017 Commercial $ 1,552,783 $ 93,823 $ 1,646,606 Commercial real estate 2,985,501 177,768 3,163,269 Total commercial and commercial real estate 4,538,284 271,591 4,809,875 Agricultural and agricultural real estate 451,539 60,049 511,588 Residential real estate 586,623 37,656 624,279 Consumer 432,936 14,548 447,484 Total gross loans receivable held to maturity $ 6,009,382 $ 383,844 $ 6,393,226 The nonpass category in the table above is comprised of approximately 53% special mention loans and 47% substandard loans as of September 30, 2018 . The percent of nonpass loans on nonaccrual status as of September 30, 2018 , was 16% . As of December 31, 2017 , the nonpass category in the table above was comprised of approximately 52% special mention loans and 48% substandard loans. The percent of nonpass loans on nonaccrual status as of December 31, 2017 , was 16% . Loans delinquent 30 to 89 days as a percent of total loans were 0.62% at September 30, 2018 , compared to 0 .27% at December 31, 2017 . Changes in credit risk are monitored on a regular basis and changes in risk ratings are made when identified. All impaired loans are reviewed at least annually. As of September 30, 2018 , Heartland had $ 3.1 million of loans secured by residential real estate property that were in the process of foreclosure. The following table sets forth information regarding Heartland's accruing and nonaccrual loans at September 30, 2018 , and December 31, 2017 , in thousands: Accruing Loans 30-59 Days Past Due 60-89 Days 90 Days or More Past Due Total Past Due Current Nonaccrual Total Loans September 30, 2018 Commercial $ 10,558 $ 3,521 $ 61 $ 14,140 $ 1,924,173 $ 23,909 $ 1,962,222 Commercial real estate 11,495 9,036 58 20,589 3,616,737 11,405 3,648,731 Total commercial and commercial real estate 22,053 12,557 119 34,729 5,540,910 35,314 5,610,953 Agricultural and agricultural real estate 1,294 1,146 35 2,475 554,055 17,518 574,048 Residential real estate 2,893 192 — 3,085 659,662 14,194 676,941 Consumer 4,493 811 — 5,304 494,843 6,034 506,181 Total gross loans receivable held to maturity $ 30,733 $ 14,706 $ 154 $ 45,593 $ 7,249,470 $ 73,060 $ 7,368,123 December 31, 2017 Commercial $ 1,246 $ 259 $ 100 $ 1,605 $ 1,637,773 $ 7,228 $ 1,646,606 Commercial real estate 4,769 2,326 — 7,095 3,139,576 16,598 3,163,269 Total commercial and commercial real estate 6,015 2,585 100 8,700 4,777,349 23,826 4,809,875 Agricultural and agricultural real estate 604 134 — 738 497,546 13,304 511,588 Residential real estate 2,022 270 — 2,292 601,120 20,867 624,279 Consumer 4,734 943 730 6,407 436,493 4,584 447,484 Total gross loans receivable held to maturity $ 13,375 $ 3,932 $ 830 $ 18,137 $ 6,312,508 $ 62,581 $ 6,393,226 The majority of Heartland's impaired loans are on nonaccrual or have had their terms restructured in a troubled debt restructuring. The following tables present, by category of loan, impaired loans, the unpaid contractual loan balances at September 30, 2018 , and December 31, 2017 ; the outstanding loan balances recorded on the consolidated balance sheets at September 30, 2018 , and December 31, 2017 ; any related allowance recorded for those loans as of September 30, 2018 , and December 31, 2017 ; the average outstanding loan balances recorded on the consolidated balance sheets during the three- and nine- months ended September 30, 2018 , and year ended December 31, 2017 ; and the interest income recognized on the impaired loans during the three- and nine- month periods ended September 30, 2018 , and year ended December 31, 2017 , in thousands: Unpaid Contractual Balance Loan Balance Related Allowance Recorded Quarter- to- Date Avg. Loan Balance Quarter- to- Date Interest Income Recognized Year- to- Date Avg. Loan Balance Year- to- Date Interest Income Recognized September 30, 2018 Impaired loans with a related allowance: Commercial $ 6,768 $ 6,768 $ 4,165 $ 5,173 $ 16 $ 3,593 $ 52 Commercial real estate 748 748 214 889 4 5,635 20 Total commercial and commercial real estate 7,516 7,516 4,379 6,062 20 9,228 72 Agricultural and agricultural real estate 2,043 2,043 260 3,000 2 2,369 2 Residential real estate 869 869 279 1,006 4 1,278 10 Consumer 3,028 3,028 1,085 3,146 9 3,069 29 Total impaired loans with a related allowance $ 13,456 $ 13,456 $ 6,003 $ 13,214 $ 35 $ 15,944 $ 113 Impaired loans without a related allowance: Commercial $ 18,003 $ 16,646 $ — $ 13,113 $ 182 $ 9,307 $ 277 Commercial real estate 13,765 13,667 — 11,850 80 12,847 201 Total commercial and commercial real estate 31,768 30,313 — 24,963 262 22,154 478 Agricultural and agricultural real estate 18,002 15,479 — 15,837 1 14,726 4 Residential real estate 22,778 22,778 — 22,779 121 24,780 320 Consumer 5,643 5,643 — 5,522 22 4,930 78 Total impaired loans without a related allowance $ 78,191 $ 74,213 $ — $ 69,101 $ 406 $ 66,590 $ 880 Total impaired loans held to maturity: Commercial $ 24,771 $ 23,414 $ 4,165 $ 18,286 $ 198 $ 12,900 $ 329 Commercial real estate 14,513 14,415 214 12,739 84 18,482 221 Total commercial and commercial real estate 39,284 37,829 4,379 31,025 282 31,382 550 Agricultural and agricultural real estate 20,045 17,522 260 18,837 3 17,095 6 Residential real estate 23,647 23,647 279 23,785 125 26,058 330 Consumer 8,671 8,671 1,085 8,668 31 7,999 107 Total impaired loans held to maturity $ 91,647 $ 87,669 $ 6,003 $ 82,315 $ 441 $ 82,534 $ 993 Unpaid Contractual Balance Loan Balance Related Allowance Recorded Year-to- Date Avg. Loan Balance Year-to- Date Interest Income Recognized December 31, 2017 Impaired loans with a related allowance: Commercial $ 2,292 $ 2,292 $ 1,613 $ 3,607 $ 39 Commercial real estate 11,925 10,068 766 11,479 34 Total commercial and commercial real estate 14,217 12,360 2,379 15,086 73 Agricultural and agricultural real estate 1,539 1,539 546 3,437 — Residential real estate 1,568 1,568 430 2,056 15 Consumer 2,634 2,634 1,400 2,370 41 Total impaired loans with a related allowance $ 19,958 $ 18,101 $ 4,755 $ 22,949 $ 129 Impaired loans without a related allowance: Commercial $ 6,243 $ 5,123 $ — $ 2,586 $ 165 Commercial real estate 14,243 13,637 — 20,148 514 Total commercial and commercial real estate 20,486 18,760 — 22,734 679 Agricultural and agricultural real estate 13,793 11,765 — 9,654 — Residential real estate 25,573 25,573 — 26,024 277 Consumer 4,269 4,269 — 3,884 73 Total impaired loans without a related allowance $ 64,121 $ 60,367 $ — $ 62,296 $ 1,029 Total impaired loans held to maturity: Commercial $ 8,535 $ 7,415 $ 1,613 $ 6,193 $ 204 Commercial real estate 26,168 23,705 766 31,627 548 Total commercial and commercial real estate 34,703 31,120 2,379 37,820 752 Agricultural and agricultural real estate 15,332 13,304 546 13,091 — Residential real estate 27,141 27,141 430 28,080 292 Consumer 6,903 6,903 1,400 6,254 114 Total impaired loans held to maturity $ 84,079 $ 78,468 $ 4,755 $ 85,245 $ 1,158 On May 18, 2018, Heartland completed the acquisition of First Bank Lubbock Bancshares, Inc., parent company of First Bank & Trust, headquartered in Lubbock, Texas. As of May 18, 2018, First Bank Lubbock Bancshares, Inc. had gross loans of $696.9 million , and the estimated fair value of the loans acquired was $681.1 million . On February 23, 2018, Heartland acquired Signature Bancshares, Inc., parent company of Signature Bank, based in Minnetonka, Minnesota. As of February 23, 2018, Signature Bancshares, Inc. had gross loans of $ 335.1 million and the estimated fair value of the loans acquired was $ 324.5 million . Included in loans acquired from Signature Bank was a lease portfolio with a fair value of $16.0 million on the acquisition date. The lease portfolio is included with the commercial loan category for disclosure purposes. Heartland uses the acquisition method of accounting for purchased loans in accordance with ASC 805, " Business Combinations." Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date, but the purchaser cannot carry over the related allowance for loan losses. Purchased loans are accounted for under ASC 310-30, " Loans and Debt Securities with Deteriorated Credit Quality," when the loans have evidence of credit deterioration since origination, and when at the date of the acquisition, it is probable that Heartland will not collect all contractually required principal and interest payments. Evidence of credit quality deterioration at the purchase date includes statistics such as past due and nonaccrual status. Generally, acquired loans that meet Heartland’s definition for nonaccrual status fall within the scope of ASC 310-30. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable difference, which is included in the carrying value of the loans. Subsequent decreases to the expected cash flows of the loan will generally result in a provision for loan losses. Subsequent increases in cash flows result in a reversal of the provision for loan losses to the extent of prior charges, or a reclassification of the difference from nonaccretable to accretable with a positive impact on future interest income. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan when there is a reasonable expectation about the amount and timing of such cash flows. At September 30, 2018 , and December 31, 2017 , the carrying amount of loans acquired since 2015 consist of purchased impaired and nonimpaired loans as summarized in the following table, in thousands: September 30, 2018 December 31, 2017 Impaired Non Impaired Total Loans Impaired Non Impaired Total Loans Commercial $ 9,078 $ 300,261 $ 309,339 $ 952 $ 187,375 $ 188,327 Commercial real estate 302 1,202,537 1,202,839 2,572 1,052,469 1,055,041 Agricultural and agricultural real estate — 32,357 32,357 — 1,242 1,242 Residential real estate 220 204,414 204,634 214 173,909 174,123 Consumer loans — 89,061 89,061 — 51,292 51,292 Total loans $ 9,600 $ 1,828,630 $ 1,838,230 $ 3,738 $ 1,466,287 $ 1,470,025 Changes in accretable yield on acquired loans with evidence of credit deterioration at the date of acquisition for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , were as follows, in thousands: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Balance at beginning of period $ 463 $ 101 $ 57 $ 182 Original yield discount, net, at date of acquisition — — 508 — Accretion (93 ) (700 ) (943 ) (1,074 ) Reclassification from nonaccretable difference (1) 186 654 934 947 Balance at period end $ 556 $ 55 $ 556 $ 55 (1) Represents increases in estimated cash flows expected to be received, primarily due to lower estimated credit losses. For loans acquired since January 2015, on the acquisition dates the preliminary estimate of the contractually required payments receivable for all loans with evidence of credit deterioration since origination was $36.9 million , and the estimated fair value of these loans was $21.8 million . At September 30, 2018 , a majority of these loans were valued based upon the liquidation value of the underlying collateral, because the expected cash flows are primarily based on the liquidation of such collateral, and the timing and amount of the cash flows could not be reasonably estimated. At September 30, 2018 , there was $ 675,000 of allowance recorded and $139,000 of allowance recorded at December 31, 2017, related to these ASC 310-30 loans. Provision expense of $675,000 and $5,000 was recorded for the nine -month periods ended September 30, 2018 , and 2017 , respectively. For loans acquired since January 2015, the preliminary estimate on the acquisition dates of the contractually required payments receivable for all nonimpaired loans acquired was $3.67 billion , and the estimated fair value of the loans was $3.59 billion .

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2018
Loans and Leases Receivable Disclosure [Abstract]
Allowance for Loan Losses	ALLOWANCE FOR LOAN LOSSES Changes in the allowance for loan losses for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , were as follows, in thousands: Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at June 30, 2018 $ 20,709 $ 23,727 $ 5,709 $ 1,857 $ 9,322 $ 61,324 Charge-offs (2,945 ) (199 ) (1,145 ) — (1,831 ) (6,120 ) Recoveries 158 242 — 1 378 779 Provision 4,147 (80 ) 2 (8 ) 1,177 5,238 Balance at September 30, 2018 $ 22,069 $ 23,690 $ 4,566 $ 1,850 $ 9,046 $ 61,221 Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at December 31, 2017 $ 18,098 $ 21,950 $ 4,258 $ 2,224 $ 9,156 $ 55,686 Charge-offs (4,717 ) (761 ) (1,357 ) (211 ) (4,462 ) (11,508 ) Recoveries 562 1,013 14 77 1,045 2,711 Provision 8,126 1,488 1,651 (240 ) 3,307 14,332 Balance at September 30, 2018 $ 22,069 $ 23,690 $ 4,566 $ 1,850 $ 9,046 $ 61,221 Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at June 30, 2017 $ 17,168 $ 21,861 $ 3,832 $ 2,263 $ 8,927 $ 54,051 Charge-offs (1,954 ) (1,913 ) — (142 ) (1,750 ) (5,759 ) Recoveries 347 46 14 63 418 888 Provision 1,409 546 2,281 82 1,387 5,705 Balance at September 30, 2017 $ 16,970 $ 20,540 $ 6,127 $ 2,266 $ 8,982 $ 54,885 Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at December 31, 2016 $ 14,765 $ 24,319 $ 4,210 $ 2,263 $ 8,767 $ 54,324 Charge-offs (3,310 ) (2,522 ) (888 ) (541 ) (4,982 ) (12,243 ) Recoveries 635 860 17 70 987 2,569 Provision 4,880 (2,117 ) 2,788 474 4,210 10,235 Balance at September 30, 2017 $ 16,970 $ 20,540 $ 6,127 $ 2,266 $ 8,982 $ 54,885 Management allocates the allowance for loan losses by pools of risk within each loan portfolio. The allocation of the allowance for loan losses by loan portfolio is made for analytical purposes and is not necessarily indicative of the trend of future loan losses in any particular category. The total allowance for loan losses is available to absorb losses from any segment of the loan portfolio.

Goodwill, Core Deposit Premium

Goodwill, Core Deposit Premium and Other Intangible Assets	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Core Deposit Premium and Other Intangible Assets	GOODWILL, CORE DEPOSIT PREMIUM AND OTHER INTANGIBLE ASSETS Heartland had goodwill of $ 391.7 million at September 30, 2018 , and $236.6 million at December 31, 2017 . Heartland conducts its annual internal assessment of the goodwill both at the consolidated level and at its subsidiaries as of September 30. There was no goodwill impairment as of the most recent assessment. Heartland recorded $121.4 million of goodwill and $13.9 million of core deposit intangibles in connection with the acquisition of First Bank Lubbock Bancshares, Inc., parent company of First Bank & Trust Company, headquartered in Lubbock, Texas on May 18, 2018. Heartland recorded $33.7 million of goodwill and $7.7 million of core deposit intangibles in connection with the acquisition of Signature Bancshares, Inc., parent company of Signature Bank, headquartered in Minnetonka, Minnesota on February 23, 2018. Heartland recorded $95.2 million of goodwill and $16.0 million of core deposit intangibles in connection with the acquisition of Citywide Banks of Colorado, Inc., parent company of Citywide Banks, headquartered in Aurora, Colorado on July 7, 2017. Heartland recorded $13.8 million of goodwill and $2.5 million of core deposit intangibles in connection with the acquisition of Founders Bancorp, parent company of Founders Community Bank, based in San Luis Obispo, California on February 28, 2017. The core deposit intangibles recorded with the First Bank Lubbock Bancshares, Inc., Signature Bancshares, Inc., Citywide Banks of Colorado, Inc., and Founders Bancorp acquisitions are not deductible for tax purposes and are expected to be amortized over a period of 10 years on an accelerated basis. Goodwill related to the First Bank Lubbock Bancshares, Inc., Signature Bancshares, Inc., Citywide Banks of Colorado, Inc., and Founders Bancorp acquisitions resulted from expected operational synergies, increased market presence, cross-selling opportunities, and expanded business lines and is not deductible for tax purposes. Heartland's intangible assets consist of core deposit intangibles, mortgage servicing rights, customer relationship intangibles, and commercial servicing rights. The gross carrying amount of these intangible assets and the associated accumulated amortization at September 30, 2018 , and December 31, 2017 , are presented in the table below, in thousands: September 30, 2018 December 31, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Amortizing intangible assets: Core deposit intangibles $ 83,639 $ 33,820 $ 49,819 $ 62,008 $ 27,086 $ 34,922 Customer relationship intangibles 1,177 925 252 1,177 896 281 Mortgage servicing rights 42,616 12,445 30,171 42,139 18,891 23,248 Commercial servicing rights 6,800 4,932 1,868 6,719 4,110 2,609 Total $ 134,232 $ 52,122 $ 82,110 $ 112,043 $ 50,983 $ 61,060 The following table shows the estimated future amortization expense for amortizable intangible assets, in thousands: Core Deposit Intangibles Customer Relationship Intangibles Mortgage Servicing Rights Commercial Servicing Rights Total Three months ending December 31, 2018 $ 2,583 $ 10 $ 1,642 $ 139 $ 4,374 Year ending December 31, 2019 9,452 38 7,132 485 17,107 2020 8,230 37 6,113 379 14,759 2021 7,036 35 5,094 331 12,496 2022 5,634 34 4,076 270 10,014 2023 4,933 34 3,057 154 8,178 Thereafter 11,951 64 3,057 110 15,182 Total $ 49,819 $ 252 $ 30,171 $ 1,868 $ 82,110 Projections of amortization expense for mortgage servicing rights are based on existing asset balances and the existing interest rate environment as of September 30, 2018 . Heartland's actual experience may be significantly different depending upon changes in mortgage interest rates and market conditions. Mortgage loans serviced for others were approximately $4.16 billion and $ 3.56 billion as of September 30, 2018 , and December 31, 2017 , respectively. Custodial escrow balances maintained in connection with the mortgage loan servicing portfolio were approximately $43.2 million and $17.3 million as of September 30, 2018 , and December 31, 2017 , respectively. The fair value of Heartland's mortgage servicing rights was estimated at $47.6 million at September 30, 2018 , and $37.1 million at December 31, 2017 . Heartland acquired the right to service mortgage loans totaling $640.7 million and a fair value of $7.0 million with the First Bank Lubbock Bancshares, Inc. transaction that closed on May 18, 2018. Heartland's mortgage servicing rights portfolio is comprised of loans serviced for the Federal National Mortgage Association ("FNMA") and the Federal Home Loan Mortgage Corporation ("FHLMC"). Prior to the third quarter of 2017, Heartland also serviced loans for the Government National Mortgage Association ("GNMA"). The servicing rights portfolio is separated into 15 - and 30 -year tranches, and the servicing rights portfolio is an asset of two of Heartland's subsidiaries. During the third quarter of 2017, Heartland entered into an agreement to sell substantially all of its GNMA servicing portfolio, which contained loans with an unpaid principal balance of approximately $773.9 million . The transaction qualified as a sale, and $6.9 million of mortgage servicing rights were de-recognized on the consolidated balance sheet as of December 31, 2017 . The fair value of mortgage servicing rights is calculated based upon a discounted cash flow analysis. Cash flow assumptions, including prepayment speeds, servicing costs and escrow earnings are considered in the calculation. The average constant prepayment rate was 8.46% and 9.73% for the September 30, 2018 , and December 31, 2017 , valuations, respectively. The discount rate was 9.19% and 9.06% for the September 30, 2018 , and December 31, 2017 , valuations, respectively. The average capitalization rate for the first nine months of 2018 ranged from 89 to 125 basis points compared to the range of 94 to 150 basis points for 2017 . Fees collected for the servicing of mortgage loans for others were $ 2.6 million and $ 2.9 million for the quarters ended September 30, 2018 , and September 30, 2017 , respectively, and $7.3 million and $9.3 million for the nine -months ended September 30, 2018 , and September 30, 2017 , respectively. The following table summarizes, in thousands, the changes in capitalized mortgage servicing rights for the nine months ended September 30, 2018 , and September 30, 2017 : 2018 2017 Balance at January 1, $ 23,248 $ 32,088 Originations 4,322 5,778 Amortization (4,394 ) (7,184 ) Valuation allowance on mortgage servicing rights — — Sale of mortgage servicing rights — (6,940 ) Acquired mortgage servicing rights 6,995 — Balance at period end $ 30,171 $ 23,742 Fair value of mortgage servicing rights $ 47,581 $ 35,002 Mortgage servicing rights, net to servicing portfolio 0.73 % 0.67 % Heartland's commercial servicing portfolio is comprised of loans guaranteed by the Small Business Administration and United States Department of Agriculture that have been sold with servicing retained by Heartland, which totaled $114.5 million at September 30, 2018 and $139.9 million at December 31, 2017. The commercial servicing rights portfolio is separated into two tranches at the respective Heartland subsidiary, loans with a term of less than 20 years and loans with a term of more than 20 years . Fees collected for the servicing of commercial loans for others were $401,000 and $394,000 for the quarter ended September 30, 2018 , and September 30, 2017 , respectively, and $1.2 million for both the nine -months ended September 30, 2018 , and September 30, 2017 , respectively. The fair value of each commercial servicing rights portfolio is calculated based upon a discounted cash flow analysis. Cash flow assumptions, including prepayment speeds and servicing costs, are considered in the calculation. The range of average constant prepayment rates for the valuations was 9.64% to 11.94% as of September 30, 2018 , compared to 7.27% to 8.88% as of December 31, 2017 . The discount rate range was 13.28% to 16.55% for the September 30, 2018 , valuations compared to 13.04% to 15.49% for the December 31, 2017 , valuations. The capitalization rate for both 2018 and 2017 ranged from 310 to 445 basis points. The total fair value of Heartland's commercial servicing rights was estimated at $2.5 million as of September 30, 2018 , and $ 3.2 million as of December 31, 2017. The following table summarizes, in thousands, the changes in capitalized commercial servicing rights for the nine -months ended September 30, 2018 , and September 30, 2017 : 2018 2017 Balance at January 1, $ 2,609 $ 3,690 Originations 82 215 Amortization (835 ) (1,077 ) Valuation allowance on commercial servicing rights 12 29 Balance at period end $ 1,868 $ 2,857 Fair value of commercial servicing rights $ 2,529 $ 3,458 Commercial servicing rights, net to servicing portfolio 1.63 % 1.98 % Mortgage and commercial servicing rights are initially recorded at fair value in net gains on sale of loans held for sale when they are acquired through loan sales. Fair value is based on market prices for comparable servicing contracts, when available, or based on a valuation model that calculates the present value of estimated future net servicing income. Mortgage and commercial servicing rights are subsequently measured using the amortization method, which requires the asset to be amortized into noninterest income in proportion to, and over the period of, the estimated future net servicing income of the underlying loans. Servicing rights are evaluated for impairment at each Heartland subsidiary based upon the fair value of the assets as compared to the carrying amount. Impairment is recognized through a valuation allowance for specific tranches to the extent that fair value is less than carrying amount at each Heartland subsidiary. At both September 30, 2018 and December 31, 2017 , no valuation allowance was required on mortgage servicing rights. At September 30, 2018 , no valuation allowance was required on commercial servicing rights with a term less than 20 years and no valuation allowance was required on commercial servicing rights with a term greater than 20 years . At December 31, 2017 , no valuation allowance was required on commercial servicing rights with a term less than 20 years and a $12,000 valuation allowance was required on commercial servicing rights with a term greater than 20 years . The following table summarizes, in thousands, the book value, the fair value of each tranche of the mortgage servicing rights and any recorded valuation allowance at each respective subsidiary at September 30, 2018 , and December 31, 2017 : September 30, 2018 Book Value 15-Year Tranche Fair Value 15-Year Tranche Impairment 15-Year Tranche Book Value 30-Year Tranche Fair Value 30-Year Tranche Impairment 30-Year Tranche Dubuque Bank and Trust Company $ 2,371 $ 4,747 $ — $ 20,632 $ 35,610 $ — First Bank & Trust 1,685 1,741 — 5,483 5,483 — Total $ 4,056 $ 6,488 $ — $ 26,115 $ 41,093 $ — December 31, 2017 Dubuque Bank and Trust Company $ 2,858 $ 4,988 $ — $ 20,390 $ 32,093 $ — Total $ 2,858 $ 4,988 $ — $ 20,390 $ 32,093 $ — The following table summarizes, in thousands, the book value, the fair value of each tranche of the commercial servicing rights and any recorded valuation allowance at each respective subsidiary at September 30, 2018 , and December 31, 2017 : September 30, 2018 Book Value Less than 20 Years Fair Value Less than 20 Years Impairment Less than 20 Years Book Value More than 20 Years Fair Value More than 20 Years Impairment More than 20 Years Citywide Banks $ 2 $ 6 $ — $ 30 $ 33 $ — Premier Valley Bank 53 82 — 188 203 — Wisconsin Bank & Trust 260 519 — 1,335 1,686 — Total $ 315 $ 607 $ — $ 1,553 $ 1,922 $ — December 31, 2017 Citywide Banks $ 8 $ 11 $ — $ 34 $ 37 $ — Premier Valley Bank 83 110 — 303 291 12 Wisconsin Bank & Trust 446 619 — 1,747 2,153 — Total $ 537 $ 740 $ — $ 2,084 $ 2,481 $ 12

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	DERIVATIVE FINANCIAL INSTRUMENTS Heartland uses derivative financial instruments as part of its interest rate risk management strategy. As part of the strategy, Heartland considers the use of interest rate swaps, caps, floors, collars, and certain interest rate lock commitments and forward sales of securities related to mortgage banking activities. Heartland's current strategy includes the use of interest rate swaps, interest rate lock commitments and forward sales of mortgage securities. In addition, Heartland is facilitating back-to-back loan swaps to assist customers in managing interest rate risk. Heartland's objectives are to add stability to its net interest margin and to manage its exposure to movements in interest rates. The contract or notional amount of a derivative is used to determine, along with the other terms of the derivative, the amounts to be exchanged between the counterparties. Heartland is exposed to credit risk in the event of nonperformance by counterparties to financial instruments. Heartland minimizes this risk by entering into derivative contracts with counterparties that meet Heartland’s credit standards, and the contracts contain collateral provisions protecting the at-risk party. Heartland has not experienced any losses from nonperformance by these counterparties. Heartland monitors counterparty risk in accordance with the provisions of ASC 815. In addition, interest rate-related derivative instruments generally contain language outlining collateral pledging requirements for each counterparty. Collateral must be posted when the market value exceeds certain threshold limits which are determined by credit ratings of each counterparty. Heartland was required to pledge no cash as collateral at September 30, 2018 , and $1.2 million at December 31, 2017 . At September 30, 2018 , $2.0 million of collateral was required to be pledged by Heartland's counterparties, compared to no collateral at December 31, 2017 . Heartland's derivative and hedging instruments are recorded at fair value on the consolidated balance sheets. See Note 8, “Fair Value,” for additional fair value information and disclosures. Cash Flow Hedges Heartland has variable rate funding which creates exposure to variability in interest payments due to changes in interest rates. To manage the interest rate risk related to the variability of interest payments, Heartland has entered into various interest rate swap agreements. Amounts reported in accumulated other comprehensive income related to derivatives will be reclassified to interest expense as interest payments are received or made on Heartland's variable-rate liabilities. For the nine months ended September 30, 2018 , the change in net unrealized losses on cash flow hedges reflects changes in the fair value of the swaps and reclassification from accumulated other comprehensive income to interest expense totaling $207,000 . For the next twelve months, Heartland estimates that cash receipts and reclassification from accumulated other comprehensive income to reduce interest expense will total $83,000 . Heartland entered into six forward starting interest rate swap transactions to effectively convert Heartland Financial Statutory Trust IV, V, VI, and VII, which total $ 85.0 million , as well as Morrill Statutory Trust I and II, which total $ 20.0 million , from variable rate subordinated debentures to fixed rate debt. For accounting purposes, these six swap transactions are designated as cash flow hedges of the changes in LIBOR, the benchmark interest rate being hedged, associated with the interest payments made on $105.0 million of Heartland's subordinated debentures that reset quarterly on a specified reset date. At inception, Heartland asserted that the underlying principal balance would remain outstanding throughout the hedge transaction, making it probable that sufficient LIBOR-based interest payments would exist through the maturity date of the swaps. On May 18, 2018, Heartland acquired cash flow hedges related to OCGI Statutory Trust III and OCGI Capital Trust IV with notional amounts of $3.0 million and $6.0 million , respectively, in the First Bank Lubbock Bancshares, Inc. transaction. The cash flow hedges effectively convert OCGI Statutory Trust III and OGCI Capital Trust IV from variable rate subordinated debentures to fixed rate debt. These swaps are designated as cash flow hedges of the changes in LIBOR, the benchmark interest rate being hedged, associated with the interest payments made on $9.0 million of Heartland's subordinated debentures that reset quarterly on a specified reset date. The table below identifies the balance sheet category and fair values of Heartland's derivative instruments designated as cash flow hedges at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category Receive Rate Weighted Average Pay Rate Maturity September 30, 2018 Interest rate swap $ 25,000 $ 424 Other assets 2.334 % 2.255 % 03/17/2021 Interest rate swap 20,000 (186 ) Other liabilities 2.339 3.355 01/07/2020 Interest rate swap 10,000 42 Other assets 2.374 1.674 03/26/2019 Interest rate swap 10,000 42 Other assets 2.334 1.658 03/18/2019 Interest rate swap 30,667 1,089 Other assets 4.633 3.674 05/10/2021 Interest rate swap 29,500 (33 ) Other liabilities 4.712 5.425 07/24/2028 Interest rate swap 20,000 652 Other assets 2.334 2.390 06/15/2024 Interest rate swap 20,000 666 Other assets 2.321 2.352 03/01/2024 Interest rate swap 6,000 175 Other assets 2.334 1.866 06/15/2021 Interest rate swap 3,000 92 Other assets 2.436 1.878 06/30/2021 December 31, 2017 Interest rate swap $ 25,000 $ (106 ) Other liabilities 1.600 % 2.255 % 03/17/2021 Interest rate swap 20,000 (621 ) Other liabilities 1.350 3.355 01/07/2020 Interest rate swap 10,000 30 Other assets 1.329 1.674 03/26/2019 Interest rate swap 10,000 29 Other assets 1.600 1.658 03/18/2019 Interest rate swap 33,667 759 Other assets 3.932 3.674 05/10/2021 Interest rate swap 20,000 (177 ) Other liabilities 1.588 2.390 06/15/2024 Interest rate swap 20,000 (149 ) Other Liabilities 1.481 2.352 03/01/2024 The table below identifies the gains and losses recognized on Heartland's derivative instruments designated as cash flow hedges for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Effective Portion Ineffective Portion Recognized in OCI Reclassified from AOCI into Income Recognized in Income on Derivatives Amount of Gain (Loss) Category Amount of Gain (Loss) Category Amount of Gain (Loss) Three Months Ended September 30, 2018 Interest rate swaps $ 375 Interest expense $ 21 Other income $ — Nine Months Ended September 30, 2018 Interest rate swaps $ 3,198 Interest expense $ (207 ) Other income $ — Three Months Ended September 30, 2017 Interest rate swaps $ 325 Interest expense $ (308 ) Other income $ — Nine Months Ended September 30, 2017 Interest rate swaps $ 349 Interest expense $ (1,005 ) Other income $ — Fair Value Hedges Heartland uses interest rate swaps to convert certain long term fixed rate loans to floating rates to hedge interest rate risk exposure. Heartland uses hedge accounting in accordance with ASC 815, with the unrealized gains and losses, representing the change in fair value of the derivative and the change in fair value of the risk being hedged on the related loan, being recorded in the consolidated statements of income. The ineffective portions of the unrealized gains or losses, if any, are recorded in interest income and interest expense in the consolidated statements of income. Heartland uses statistical regression to assess hedge effectiveness, both at the inception of the hedge as well as on a continual basis. The regression analysis involves regressing the periodic change in the fair value of the hedging instrument against the periodic changes in the fair value of the asset being hedged due to changes in the hedge risk. Heartland was required to pledge $3.2 million and $3.9 million of cash as collateral for these fair value hedges at September 30, 2018 , and December 31, 2017 , respectively. The table below identifies the notional amount, fair value and balance sheet category of Heartland's fair value hedges at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category September 30, 2018 Fair value hedges $ 30,954 $ 625 Other assets Fair value hedges 4,133 (201 ) Other liabilities December 31, 2017 Fair value hedges $ 35,635 $ (999 ) Other liabilities The table below identifies the gains and losses recognized on Heartland's fair value hedges for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Amount of Gain (Loss) Income Statement Category Three Months Ended September 30, 2018 Fair value hedges $ 179 Interest income Nine Months Ended September 30, 2018 Fair value hedges $ 1,423 Interest income Three Months Ended September 30, 2017 Fair value hedges $ (63 ) Interest income Nine Months Ended September 30, 2017 Fair value hedges $ 89 Interest income Embedded Derivatives Heartland has fixed rate loans with embedded derivatives. The loans contain terms that affect the cash flows or value of the loan similar to a derivative instrument, and therefore are considered to contain an embedded derivative. The embedded derivatives are bifurcated from the loans because the terms of the derivative instrument are not clearly and closely related to the loans. The embedded derivatives are recorded at fair value on the consolidated balance sheets as a part of other assets, and changes in the fair value are a component of noninterest income. The table below identifies the notional amount, fair value and balance sheet category of Heartland's embedded derivatives at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category September 30, 2018 Embedded derivatives $ 13,643 $ 215 Other assets December 31, 2017 Embedded derivatives $ 14,045 $ 738 Other assets The table below identifies the gains and losses recognized on Heartland's embedded derivatives for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Amount of Gain (Loss) Income Statement Category Three Months Ended September 30, 2018 Embedded derivatives $ 108 Other noninterest income Nine Months Ended September 30, 2018 Embedded derivatives $ 523 Other noninterest income Three Months Ended September 30, 2017 Embedded derivatives $ (296 ) Other noninterest income Nine Months Ended September 30, 2017 Embedded derivatives $ (181 ) Other noninterest income In conjunction with the CIC Bancshares, Inc. transaction on February 5, 2016, Heartland assumed convertible subordinated debt. The subordinated debt had a face value of $2.0 million , and the embedded conversion option allowed the holder to convert the debt to Heartland common equity in any increment and at the discretion of the holder. The conversion option was bifurcated from the debt because the terms of the conversion option are not clearly and closely related to the terms of the debt. On February 5, 2016, the total number of shares to be issued upon conversion was 73,394 . At September 30, 2018 , and December 31, 2017, the remaining shares to be issued upon conversion totaled zero . During 2017, all of the remaining convertible subordinated debt was converted to common stock, resulting in the issuance of 20,481 shares of common stock. The notional amount of the embedded conversion option was $0 at both September 30, 2018 , and December 31, 2017. For the three- and nine-month periods ended September 30, 2018 , no other noninterest income was recorded for the embedded conversion option. For the three- and nine-month periods ended September 30, 2017 , $285,000 and $422,000 , respectively, was recorded in other noninterest income for the embedded conversion option. Back-to-Back Loan Swaps Heartland has interest rate swap loan relationships with customers to meet their financing needs. Upon entering into these loan swaps, Heartland enters into offsetting positions with counterparties in order to minimize interest rate risk. These back-to-back loan swaps qualify as free standing financial derivatives with the fair values reported in other assets and other liabilities on the consolidated balance sheets. Heartland was required to post $815,000 and $1.6 million as of September 30, 2018 , and December 31, 2017 , respectively, as collateral related to these back-to-back swaps. Heartland's counterparties were required to pledge $2.5 million at September 30, 2018 , and $190,000 at December 31, 2017 . Any gains and losses on these back-to-back swaps are recorded in noninterest income on the consolidated statements of income, and for the nine months ended September 30, 2018 and September 30, 2017 , no gain or loss was recognized. The table below identifies the balance sheet category and fair values of Heartland's derivative instruments designated as loan swaps at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category Weighted Average Receive Rate Weighted Average Pay Rate September 30, 2018 Customer interest rate swaps $ 200,241 $ 5,305 Other assets 5.07 % 4.68 % Customer interest rate swaps 200,241 (5,305 ) Other liabilities 4.68 5.07 December 31, 2017 Customer interest rate swaps $ 126,766 $ 2,377 Other assets 4.70 % 4.03 % Customer interest rate swaps 126,766 (2,377 ) Other liabilities 4.03 4.70 Other Free Standing Derivatives Heartland has entered into interest rate lock commitments to originate residential mortgage loans held for sale and forward commitments to sell residential mortgage loans and mortgage backed securities that are considered derivative instruments. Heartland enters into forward commitments for the future delivery of residential mortgage loans when interest rate lock commitments are entered into in order to economically hedge the effect of future changes in interest rates on the commitments to fund the loans as well as on residential mortgage loans available for sale. The fair value of these commitments is recorded on the consolidated balance sheets, with the changes in fair value recorded in the consolidated statements of income as a component of gains on sale of loans held for sale. These derivative contracts are designated as free standing derivative contracts and are not designated against specific assets and liabilities on the consolidated balance sheets or forecasted transactions and therefore do not qualify for hedge accounting treatment. Heartland was required to pledge collateral of $35,000 at September 30, 2018 , and $20,000 at December 31, 2017 . Heartland's counterparties were required to pledge $29,000 at both September 30, 2018 , and December 31, 2017 , respectively, as collateral for these forward commitments. Heartland acquired undesignated interest rate swaps in 2015. These swaps were entered into primarily for the benefit of customers seeking to manage their interest rate risk and are not designated against specific assets or liabilities on the consolidated balance sheet or forecasted transactions and therefore do not qualify for hedge accounting in accordance with ASC 815. These swaps are carried at fair value on the consolidated balance sheets as a component of other liabilities, with changes in the fair value recorded as a component of other noninterest income. The table below identifies the balance sheet category and fair values of Heartland's other free standing derivative instruments not designated as hedging instruments at September 30, 2018 , and December 31, 2017 , in thousands: Balance Sheet Category Notional Amount Fair Value September 30, 2018 Interest rate lock commitments (mortgage) Other assets $ 52,649 $ 1,539 Forward commitments Other assets 82,500 353 Forward commitments Other liabilities 33,500 (69 ) Undesignated interest rate swaps Other liabilities 13,643 (215 ) December 31, 2017 Interest rate lock commitments (mortgage) Other assets $ 53,588 $ 1,738 Forward commitments Other assets 37,286 80 Forward commitments Other liabilities 118,632 (232 ) Undesignated interest rate swaps Other liabilities 14,045 (738 ) The table below identifies the income statement category of the gains and losses recognized in income on Heartland's other free standing derivative instruments not designated as hedging instruments for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Income Statement Category Gain (Loss) Recognized Three Months Ended September 30, 2018 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (4,470 ) Forward commitments Net gains on sale of loans held for sale 644 Undesignated interest rate swaps Other noninterest income 108 Nine Months Ended September 30, 2018 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (1,849 ) Forward commitments Net gains on sale of loans held for sale 352 Undesignated interest rate swaps Other noninterest income 523 Three Months Ended September 30, 2017 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (1,245 ) Forward commitments Net gains on sale of loans held for sale 72 Undesignated interest rate swaps Other noninterest income 88 Nine Months Ended September 30, 2017 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (587 ) Forward commitments Net gains on sale of loans held for sale (2,304 ) Undesignated interest rate swaps Other noninterest income 203

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE Heartland utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. Securities carried at fair value, which include available for sale, trading securities and equity securities with a readily determinable fair value, and derivatives are recorded in the consolidated balance sheets at fair value on a recurring basis. Additionally, from time to time, Heartland may be required to record at fair value other assets on a nonrecurring basis such as loans held for sale, loans held to maturity and certain other assets including, but not limited to, mortgage servicing rights, commercial servicing rights and other real estate owned. These nonrecurring fair value adjustments typically involve application of the lower of cost or fair value accounting or write-downs of individual assets. Fair Value Hierarchy Under ASC 820, assets and liabilities are grouped at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: Level 1 — Valuation is based upon quoted prices for identical instruments in active markets. Level 2 — Valuation is based upon quoted prices for similar instruments in active markets, or similar instruments in markets that are not active, and model-based valuation techniques for all significant assumptions are observable in the market. Level 3 — Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques. The following is a description of valuation methodologies used for assets and liabilities recorded at fair value on a recurring or non-recurring basis. Assets Securities Available for Sale and Held to Maturity Securities available for sale are recorded at fair value on a recurring basis. Securities held to maturity are generally recorded at cost and are recorded at fair value only to the extent a decline in fair value is determined to be other-than-temporary. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security's credit rating, prepayment assumptions and other factors such as credit loss assumptions. Level 1 securities include those traded on an active exchange, such as the New York Stock Exchange, as well as U.S. Treasury securities. Level 2 securities include U.S. government and agency securities, mortgage and asset-backed securities and private collateralized mortgage obligations, municipal bonds and corporate debt securities. On a quarterly basis, a secondary independent pricing service is used for the securities portfolio to validate the pricing from Heartland's primary pricing service. Loans Held for Sale Loans held for sale are carried at the lower of cost or fair value on an aggregate basis. The fair value of loans held for sale is based on what secondary markets are currently offering for portfolios with similar characteristics. As such, Heartland classifies loans held for sale subjected to nonrecurring fair value adjustments as Level 2. Loans Held to Maturity Heartland does not record loans held to maturity at fair value on a recurring basis. However, from time to time, a loan is considered impaired and an allowance for loan losses is established. Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired. Once a loan is identified as individually impaired, management measures impairment in accordance with ASC 310. The fair value of impaired loans is measured using one of the following impairment methods: 1) the present value of expected future cash flows discounted at the loan's effective interest rate or 2) the observable market price of the loan or 3) the fair value of the collateral if the loan is collateral dependent. In accordance with ASC 820, impaired loans measured at fair value are classified as nonrecurring Level 3 in the fair value hierarchy. Premises, Furniture and Equipment Held for Sale Heartland values premises, furniture and equipment held for sale based on third-party appraisals less estimated disposal costs. Heartland considers third party appraisals, as well as independent fair value assessments from Realtors or persons involved in selling bank premises, furniture and equipment, in determining the fair value of particular properties. Accordingly, the valuation of premises, furniture and equipment held for sale is subject to significant external and internal judgment. Heartland periodically reviews premises, furniture and equipment held for sale to determine if the fair value of the property, less disposal costs, has declined below its recorded book value and records any adjustments accordingly. Premises, furniture and equipment held for sale are classified as nonrecurring Level 3 in the fair value hierarchy. Mortgage Servicing Rights Mortgage servicing rights assets represent the value associated with servicing residential real estate loans that have been sold to outside investors with servicing retained. Heartland uses the amortization method (i.e., the lower of amortized cost or estimated fair value measured on a nonrecurring basis), not fair value measurement accounting, to determine the carrying value of its mortgage servicing rights. The fair value for servicing assets is determined through discounted cash flow analysis and utilizes discount rates, prepayment speeds and delinquency rate assumptions as inputs. All of the assumptions in the discounted cash flow analysis require a significant degree of management estimation and judgment. Mortgage servicing rights are subject to impairment testing. The carrying values of these rights are reviewed quarterly for impairment based upon the calculation of fair value as performed by an outside third party. For purposes of measuring impairment, the rights are stratified into certain risk characteristics including note type and note term. If the valuation model reflects a fair value less than the carrying value, mortgage servicing rights are adjusted to fair value through a valuation allowance. Heartland classifies mortgage servicing rights as nonrecurring with Level 3 measurement inputs. Commercial Servicing Rights Commercial servicing rights assets represent the value associated with servicing commercial loans guaranteed by the Small Business Administration and the United States Department of Agriculture that have been sold with servicing retained by Heartland. Heartland uses the amortization method (i.e., the lower of amortized cost or estimated fair value measured on a nonrecurring basis), not fair value measurement accounting, to determine the carrying value of its commercial servicing rights. The fair value for servicing assets is determined through market prices for comparable servicing contracts, when available, or through a valuation model that calculates the present value of estimated future net servicing income. Inputs utilized include discount rates, prepayment speeds and delinquency rate assumptions as inputs. All of these assumptions require a significant degree of management estimation and judgment. Commercial servicing rights are subject to impairment testing, and the carrying values of these rights are reviewed quarterly for impairment based upon the calculation of fair value as performed by an outside third party. If the valuation model reflects a fair value less than the carrying value, commercial servicing rights are adjusted to fair value through a valuation allowance. Heartland classifies commercial servicing rights as nonrecurring with Level 3 measurement inputs. Derivative Financial Instruments Heartland's current interest rate risk strategy includes interest rate swaps. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. To comply with the provisions of ASC 820, Heartland incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty's nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, Heartland has considered the impact of netting any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although Heartland has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2018 , and December 31, 2017 , Heartland has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, Heartland has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. Interest rate lock commitments Heartland uses an internal valuation model that relies on internally developed inputs to estimate the fair value of its interest rate lock commitments which is based on unobservable inputs that reflect management's assumptions and specific information about each borrower. Interest rate lock commitments are classified in Level 3 of the fair value hierarchy. Forward commitments The fair value of forward commitments are estimated using an internal valuation model, which includes current trade pricing for similar financial instruments in active markets that Heartland has the ability to access and are classified in Level 2 of the fair value hierarchy. Other Real Estate Owned Other real estate owned ("OREO") represents property acquired through foreclosures and settlements of loans. Property acquired is carried at the fair value of the property at the time of acquisition (representing the property's cost basis), plus any acquisition costs, or the estimated fair value of the property, less disposal costs. Heartland considers third party appraisals, as well as independent fair value assessments from realtors or persons involved in selling OREO, in determining the fair value of particular properties. Accordingly, the valuation of OREO is subject to significant external and internal judgment. Heartland periodically reviews OREO to determine if the fair value of the property, less disposal costs, has declined below its recorded book value and records any adjustments accordingly. OREO is classified as nonrecurring Level 3 of the fair value hierarchy. The table below presents Heartland's assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2018 , and December 31, 2017 , in thousands, aggregated by the level in the fair value hierarchy within which those measurements fall: Total Fair Value Level 1 Level 2 Level 3 September 30, 2018 Assets Securities available for sale U.S. government corporations and agencies $ 26,997 $ 25,367 $ 1,630 $ — Mortgage and asset-backed securities 1,871,819 — 1,871,819 — Obligations of states and political subdivisions 358,483 — 358,483 — Equity securities with a readily determinable fair value 16,916 — 16,916 — Derivative financial instruments (1) 9,327 — 9,327 — Interest rate lock commitments 1,539 — — 1,539 Forward commitments 353 — 353 — Total assets at fair value $ 2,285,434 $ 25,367 $ 2,258,528 $ 1,539 Liabilities Derivative financial instruments (2) $ 5,940 $ — $ 5,940 $ — Forward commitments 69 — 69 — Total liabilities at fair value $ 6,009 $ — $ 6,009 $ — December 31, 2017 Assets Securities available for sale U.S. government corporations and agencies $ 5,328 $ 3,484 $ 1,844 $ — Mortgage and asset-backed securities 1,753,736 — 1,753,736 — Obligations of states and political subdivisions 441,015 — 441,015 — Equity securities 16,674 — 16,674 — Derivative financial instruments (1) 3,933 — 3,933 — Interest rate lock commitments 1,738 — — 1,738 Forward commitments 80 — 80 — Total assets at fair value $ 2,222,504 $ 3,484 $ 2,217,282 $ 1,738 Liabilities Derivative financial instruments (2) $ 5,167 $ — $ 5,167 $ — Forward commitments 232 — 232 — Total liabilities at fair value $ 5,399 $ — $ 5,399 $ — (1) Includes cash flow hedges, embedded derivatives and back-to-back loan swaps (2) Includes cash flow hedges, fair value hedges, back-to-back loan swaps, embedded conversion options and free standing derivative instruments The tables below present Heartland's assets that are measured at fair value on a nonrecurring basis, in thousands: Fair Value Measurements at Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Year-to- Date (Gains) Losses Collateral dependent impaired loans: Commercial $ 6,772 $ — $ — $ 6,772 $ 237 Commercial real estate 420 — — 420 72 Agricultural and agricultural real estate 11,821 — — 11,821 495 Residential real estate 590 — — 590 — Consumer 1,942 — — 1,942 — Total collateral dependent impaired loans $ 21,545 $ — $ — $ 21,545 $ 804 Loans held for sale $ 77,727 $ — $ 77,727 $ — $ (835 ) Other real estate owned $ 11,908 $ — $ — $ 11,908 $ 1,847 Premises, furniture and equipment held for sale $ 4,422 $ — $ — $ 4,422 $ (74 ) Fair Value Measurements at December 31, 2017 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Year-to- Collateral dependent impaired loans: Commercial $ 3,212 $ — $ — $ 3,212 $ 1,119 Commercial real estate 9,480 — — 9,480 322 Agricultural and agricultural real estate 8,406 — — 8,406 2,028 Residential real estate 1,137 — — 1,137 — Consumer 1,234 — — 1,234 — Total collateral dependent impaired loans $ 23,469 $ — $ — $ 23,469 $ 3,469 Loans held for sale $ 44,560 $ — $ 44,560 $ — $ 190 Other real estate owned $ 10,777 $ — $ — $ 10,777 $ 737 Premises, furniture and equipment held for sale $ 1,977 $ — $ — $ 1,977 $ 192 Commercial servicing rights $ 291 $ — $ — $ 291 $ (21 ) The following tables present additional quantitative information about assets measured at fair value and for which Heartland has utilized Level 3 inputs to determine fair value, in thousands: Fair Value at 9/30/2018 Valuation Unobservable Range Interest rate lock commitments $ 1,539 Discounted cash flows Closing ratio 0-99% (1) Other real estate owned 11,908 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Premises, furniture and equipment held for sale 4,422 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Collateral dependent impaired loans: Commercial 6,772 Modified appraised value Third party appraisal (2) Appraisal discount 0-13% (3) Commercial real estate 420 Modified appraised value Third party appraisal (2) Appraisal discount 0-12% (3) Agricultural and agricultural real estate 11,821 Modified appraised value Third party appraisal (2) Appraisal discount 0-15% (3) Residential real estate 590 Modified appraised value Third party appraisal (2) Appraisal discount 0-24% (3) Consumer 1,942 Modified appraised value Third party valuation (2) Valuation discount 0-14% (3) (1) The significant unobservable input used in the fair value measurement is the closing ratio, which represents the percentage of loans currently in a lock position which management estimates will ultimately close. The closing ratio calculation takes into consideration historical data and loan-level data. The weighted average closing ratio for Heartland's legacy mortgage operations is 86%. The weighted average closing ratio for PrimeWest Mortgage Corporation is 95%. (2) Third party appraisals are obtained and updated at least annually to establish the value of the underlying asset, but the disclosure of the unobservable inputs used by the appraisers would not be meaningful because the range will vary widely from appraisal to appraisal. (3) Discounts applied to the appraised values primarily include estimated sales costs, but also consider the age of the appraisal, changes in local market conditions and changes in the current condition of the collateral. Fair Value at 12/31/2017 Valuation Technique Unobservable Input Range (Weighted Average) Interest rate lock commitments $ 1,738 Discounted cash flows Closing ratio 0-99% (89%) (1) Other real estate owned 10,777 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Commercial servicing rights 291 Discounted cash flows Third party valuation (3) Premises, furniture and equipment held for sale 1,977 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Other real estate owned 10,777 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Collateral dependent impaired loans: Commercial 3,212 Modified appraised value Third party appraisal (2) Appraisal discount 0-15% (3) Commercial real estate 9,480 Modified appraised value Third party appraisal (2) Appraisal discount 0-12% (3) Agricultural and agricultural real estate 8,406 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Residential real estate 1,137 Modified appraised value Third party appraisal (2) Appraisal discount 0-12% (3) Consumer 1,234 Modified appraised value Third party valuation (2) Valuation discount 0-12% (3) (1) The significant unobservable input used in the fair value measurement is the closing ratio, which represents the percentage of loans currently in a lock position which management estimates will ultimately close. The closing ratio calculation takes into consideration historical data and loan-level data. (2) Third party appraisals are obtained and updated at least annually to establish the value of the underlying asset, but the disclosure of the unobservable inputs used by the appraisers would not be meaningful because the range will vary widely from appraisal to appraisal. (3) Discounts applied to the appraised values primarily include estimated sales costs, but also consider the age of the appraisal, changes in local market conditions and changes in the current condition of the collateral. The changes in fair value of the interest rate lock commitments, which are Level 3 financial instruments measured on a recurring basis, are summarized in the following table, in thousands: For the Nine Months Ended For the Year Ended December 31, 2017 Balance at January 1, $ 1,738 $ 2,790 Acquired interest rate lock commitments 1,383 — Total gains (losses) included in earnings (1,849 ) (1,479 ) Issuances 1,661 1,875 Settlements (1,394 ) (1,448 ) Balance at period end $ 1,539 $ 1,738 Gains included in gains (losses) on sale of loans held for sale attributable to interest rate lock commitments held at September 30, 2018 , and December 31, 2017 , were $1.5 million and $1.7 million , respectively. The tables below summarize the estimated fair value of Heartland's financial instruments as defined by ASC 825 as of September 30, 2018 , and December 31, 2017 , in thousands. The carrying amounts in the following tables are recorded in the consolidated balance sheets under the indicated captions. In accordance with ASC 825, the assets and liabilities that are not financial instruments are not included in the disclosure, such as the value of the commercial and mortgage servicing rights, premises, furniture and equipment, premises, furniture and equipment held for sale, OREO, goodwill, and other intangibles and other liabilities. Heartland does not believe that the estimated information presented herein is representative of the earnings power or value of Heartland. The following analysis, which is inherently limited in depicting fair value, also does not consider any value associated with either existing customer relationships or the ability of Heartland to create value through loan origination, deposit gathering or fee generating activities. Many of the estimates presented herein are based upon the use of highly subjective information and assumptions and, accordingly, the results may not be precise. Management believes that fair value estimates may not be comparable between financial institutions due to the wide range of permitted valuation techniques and numerous estimates which must be made. Furthermore, because the disclosed fair value amounts were estimated as of the balance sheet date, the amounts actually realized or paid upon maturity or settlement of the various financial instruments could be significantly different. Fair Value Measurements at Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 437,375 $ 437,375 $ 437,375 $ — $ — Time deposits in other financial institutions 5,836 5,836 5,836 — — Securities: Carried at fair value 2,274,215 2,274,215 25,367 2,248,848 — Held to maturity 239,908 247,394 — 247,394 — Other investments 26,656 26,656 — 26,656 — Loans held for sale 77,727 77,727 — 77,727 — Loans, net: Commercial 1,939,469 1,906,941 — 1,900,169 6,772 Commercial real estate 3,623,768 3,611,265 — 3,610,845 420 Agricultural and agricultural real estate 570,320 563,262 — 551,441 11,821 Residential real estate 673,628 663,234 — 662,644 590 Consumer 497,151 494,379 — 492,437 1,942 Total Loans, net 7,304,336 7,239,081 — 7,217,536 21,545 Cash surrender value on life insurance 162,216 162,216 — 162,216 — Derivative financial instruments (1) 9,126 9,126 — 9,126 — Interest rate lock commitments 1,539 1,539 — — 1,539 Forward commitments 353 353 — 353 — Financial liabilities: Deposits Demand deposits 3,427,819 3,427,819 — 3,427,819 — Savings deposits 4,958,430 4,958,430 — 4,958,430 — Time deposits 1,125,914 1,125,914 — 1,125,914 — Short term borrowings 131,139 131,139 — 131,139 — Other borrowings 277,563 279,087 — 279,087 — Derivative financial instruments (2) 5,739 5,940 — 5,940 — Forward commitments 69 69 — 69 — (1) Includes cash flow hedges, embedded derivatives and back-to-back loan swaps (2) Includes cash flow hedges, fair value hedges, back-to-back loan swaps, embedded conversion options and free standing derivative instruments Fair Value Measurements at December 31, 2017 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 196,003 $ 196,003 $ 196,003 $ — $ — Time deposits in other financial institutions 9,820 9,820 9,820 — — Securities: Carried at fair value 2,216,753 2,216,753 3,484 2,213,269 — Held to maturity 253,550 265,494 — 265,494 — Other investments 22,563 22,563 — 22,563 — Loans held for sale 44,560 44,560 — 44,560 — Loans, net: Commercial 1,628,043 1,617,956 — 1,614,744 3,212 Commercial real estate 3,140,427 3,132,542 — 3,123,062 9,480 Agricultural and agricultural real estate 508,075 508,987 — 500,581 8,406 Residential real estate 620,939 614,667 — 613,530 1,137 Consumer 438,294 440,820 — 439,586 1,234 Total Loans, net 6,335,778 6,314,972 — 6,291,503 23,469 Cash surrender value on life insurance 142,818 142,818 — 142,818 — Derivative financial instruments (1) 3,933 3,933 — 3,933 — Interest rate lock commitments 1,738 1,738 — — 1,738 Forward commitments 80 80 — 80 — Financial liabilities: Deposits Demand deposits 2,983,128 2,983,128 — 2,983,128 — Savings deposits 4,240,328 4,240,328 — 4,240,328 — Time deposits 923,453 923,453 — 923,453 — Short term borrowings 324,691 324,691 — 324,691 — Other borrowings 285,011 285,609 — 285,609 — Derivative financial instruments (2) 5,167 5,167 — 5,167 — Forward commitments 232 232 — 232 — (1) Includes cash flow hedges, embedded derivatives and back-to-back loan swaps (2) Includes cash flow hedges, fair value hedges, back-to-back loan swaps, embedded conversion options and free standing derivative instruments Cash and Cash Equivalents — The carrying amount is a reasonable estimate of fair value due to the short-term nature of these instruments. Time Deposits in Other Financial Institutions — The carrying amount is a reasonable estimate of fair value due to the short-term nature of these instruments. Securities — For equity securities with a readily determinable fair value and debt securities either held to maturity, available for sale or trading, fair value equals quoted market price if available. If a quoted market price is not available, fair value is estimated using quoted market prices for similar securities. For Level 3 securities, Heartland utilizes independent pricing provided by third party vendors or brokers. Other Investments — Fair value measurement of other investments, which consists primarily of FHLB stock, are based on their redeemable value, which is at cost due to the restrictions placed on their transferability. The market for these securities is restricted to the issuer of the stock and subject to impairment evaluation. Loans — Beginning in the first quarter of 2018, the fair value of loans were determined using an exit price methodology as prescribed by ASU 2016-01, which was effective on January 1, 2018. The exit price estimation of fair value is based on the present value of the expected cash flows. The projected cash flows are based on the contractual terms of the loans, adjusted for prepayments and a discount rate based on the relative risk of the cash flows. Other considerations include the loan type, remaining life of the loan and credit risk. In comparison, loan fair values as of December 31, 2017, were estimated based on an entrance price methodology, which discounts future cash flows using the current rates at which a similar loan would be made to borrowers with similar credit ratings and for the same remaining maturities. The fair value of non-impaired loans as of September 30, 2018, and December 31, 2017, are not comparable. The fair value of impaired loans is measured using the fair value of the underlying collateral. The fair value of loans held for sale is estimated using quoted market prices. Interest Rate Lock Commitments — The fair value of interest rate lock commitments is estimated using an internal valuation model, which includes grouping the interest rate lock commitments by interest rate and terms, applying an estimated closing ratio based on historical experience, and then multiplying by quoted investor prices determined to be reasonably applicable to the loan commitment groups based on interest rate, terms, and rate lock expiration dates of the loan commitment group. Forward Commitments — The fair value of these instruments is estimated using an internal valuation model, which includes current trade pricing for similar financial instruments. Derivative Financial Instruments — The fair value of all derivatives is estimated based on the amount that Heartland would pay or would be paid to terminate the contract or agreement, using current rates and prices, and, when appropriate, the current creditworthiness of the counter-party. Deposits — The fair value of demand deposits, savings accounts and certain money market deposits is the amount payable on demand at the reporting date. The fair value of fixed maturity certificates of deposit is estimated using the rates currently offered for deposits of similar remaining maturities. If the fair value of the fixed maturity certificates of deposit is calculated at less than the carrying amount, the carrying value of these deposits is reported as the fair value. Short-term and Other Borrowings — Rates currently available to Heartland for debt with similar terms and remaining maturities are used to estimate fair value of existing debt. Commitments to Extend Credit, Unused Lines of Credit and Standby Letters of Credit — Based upon management's analysis of the off balance sheet financial instruments, there are no significant unrealized gains or losses associated with these financial instruments based upon review of the fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the present creditworthiness of the counterparties.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE On January 1, 2018, Heartland adopted ASU 2014-09, "Revenue from Contracts with Customers" (Topic 606), and all subsequent ASUs that modified Topic 606. As stated in Note 1, the implementation of the new standard did not have a material impact on the measurement or recognition of revenue; as such, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts were not adjusted and continue to be reported in accordance with Topic 605. Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with loan servicing income, bank owned life insurance, derivatives and certain credit card fees are also not in scope of the new guidance. Topic 606 is applicable to noninterest revenue streams such as service charges and fees, trust fees, and brokerage and insurance commissions. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Substantially all of Heartland's revenue is generated from contracts with customers. Noninterest revenue streams in-scope of Topic 606 are discussed below. Service Charges and Fees Service charges and fees consist of revenue generated from deposit account related service charges and fees, overdraft fees, customer service fees, credit card fee income, debit card income and other service charges and fees. Service charges on deposit accounts consist of account analysis fees (i.e., net fees earned on analyzed business and public checking accounts), monthly service fees, check orders and other deposit account related fees. Heartland's performance obligation for account analysis fees and monthly service fees is generally satisfied, and the related revenue recognized, over the period in which the service is provided. Check orders and other deposit account related fees, including overdraft fees, are largely transactional based, and therefore, the performance obligation is satisfied, and related revenue recognized, at a point in time. Payment for service charges on deposit accounts is primarily received immediately or in the following month through a direct charge to customers’ accounts. Customer service fees and other service charges include revenue from processing wire transfers, bill pay service, cashier’s checks, and other services. Heartland's performance obligation for fees, exchange, and other service charges are largely satisfied, and related revenue recognized, when the services are rendered or upon completion. Payment is typically received immediately or in the following month. Credit card fee income and debit card income are comprised of interchange fees, ATM fees, and merchant services income. Credit card fee income and debit card income are earned whenever the banks' debit and credit cards are processed through card payment networks such as Visa. ATM fees are primarily generated when a bank cardholder uses an ATM that is not owned by one of Heartland's banks or a non-bank cardholder uses Heartland-owned ATM. Merchant services income mainly represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. Trust Fees Trust fees are primarily comprised of fees earned from the management and administration of trusts and other customer assets. Heartland's performance obligation is generally satisfied over time and the resulting fees are recognized monthly, based upon the average daily market value or month-end market value of the assets under management and the applicable fee rate. Payment is generally received a few days before or after month end through a direct charge to customers’ accounts. Heartland does not earn performance-based incentives. Optional services such as real estate sales and tax return preparation services are also available to existing trust and asset management customers. Heartland's performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time (i.e., as incurred). Payment is received shortly after services are rendered. Brokerage and Insurance Commissions Brokerage commission primarily consist of commissions related to broker-dealer contracts. The contracts are between the customer and the broker-dealer, and Heartland satisfies its performance obligation and earns commission when the transactions are completed. The recognition of revenue is based on a defined fee schedule and does not require significant judgment. Payment is received shortly after services are rendered. Insurance commissions are related to commissions received directly from the insurance carrier. Heartland acts as an insurance agent between the customer and the insurance carrier. Heartland's performance obligations and associated fee and commission income are defined with each insurance product with the insurance company. When insurance payments are received from customers, a portion of the payment is recognized as commission revenue. The following presents noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the three- and nine-months ended September 30, 2018, and 2017, in thousands: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 In-scope of Topic 606 Service charges and fees Service charges and fees on deposit accounts $ 2,858 $ 2,577 $ 8,270 $ 7,002 Overdraft fees 2,990 2,479 7,716 6,950 Customer service fees 101 102 266 217 Credit card fee income 3,062 1,994 8,443 6,212 Debit card income 3,883 2,985 10,349 8,908 Other service charges 1 1 2 2 Total service charges and fees $ 12,895 $ 10,138 $ 35,046 $ 29,291 Trust fees 4,499 3,872 13,794 11,482 Brokerage and insurance commissions 1,111 950 2,895 2,962 Total noninterest income in-scope of Topic 606 $ 18,505 $ 14,960 $ 51,735 $ 43,735 Out-of-scope of Topic 606 Loan servicing income $ 1,670 $ 1,161 $ 5,231 $ 4,236 Securities gains/(losses), net (145 ) 1,679 1,037 5,553 Unrealized gain on equity securities, net 54 — 97 — Net gains on sale of loans held for sale 7,410 4,997 18,261 17,961 Valuation adjustment on commercial servicing rights 230 5 12 29 Income on bank owned life insurance 892 766 2,206 2,039 Other noninterest income 1,149 1,409 3,536 2,941 Total noninterest income out-of-scope of Topic 606 11,260 10,017 30,380 32,759 Total noninterest income $ 29,765 $ 24,977 $ 82,115 $ 76,494 Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity’s obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. Heartland's noninterest revenue streams are largely based on transactional activity, or standard month-end revenue accruals such as asset management fees based on month-end market values. Consideration is often received immediately or shortly after Heartland satisfies its performance obligation and revenue is recognized. Heartland does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of September 30, 2018, and December 31, 2017, Heartland did not have any significant contract balances. Contract Acquisition Costs In connection with the adoption of Topic 606, an entity is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained (for example, sales commission). Heartland utilizes the practical expedient which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, Heartland did not capitalize any contract acquisition costs.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The interim unaudited consolidated financial statements contained herein should be read in conjunction with the audited consolidated financial statements and accompanying notes to the consolidated financial statements for the fiscal year ended December 31, 2017 , included in the Form 10-K of Heartland Financial USA, Inc. ("Heartland") filed with the Securities and Exchange Commission ("SEC") on February 28, 2018 . Foot note disclosures to the interim unaudited consolidated financial statements which would substantially duplicate the disclosure contained in the footnotes to the audited consolidated financial statements have been omitted. The financial information of Heartland included herein has been prepared in accordance with U.S. generally accepted accounting principles for interim financial reporting and has been prepared pursuant to the rules and regulations for reporting on Form 10-Q and Rule 10-01 of Regulation S-X. Such information reflects all adjustments (consisting of normal recurring adjustments), that are, in the opinion of management, necessary for a fair presentation of the financial position and results of operations for the periods presented. The results of the interim period ended September 30, 2018 , are not necessarily indicative of the results expected for the year ending December 31, 2018 . In the Annual Report on Form 10-K for the year ended December 31, 2017, Heartland reported the results of operations through two business segments: Community and Other Banking and Mortgage Banking. Effective January 1, 2018, the recently restructured mortgage banking segment is no longer a reportable segment due to the significant reduction in infrastructure and the reporting structure of the mortgage sales staff, who currently report directly to the bank president in each market. Accordingly, Heartland is no longer reporting results of operations by segment.
Earnings Per Share	Basic earnings per share is determined using net income available to common stockholders and weighted average common shares outstanding. Diluted earnings per share is computed by dividing net income available to common stockholders by the weighted average common shares and assumed incremental common shares issued.
Stock-Based Compensation	Heartland may grant, through its Nominating and Compensation Committee (the "Compensation Committee"), non-qualified and incentive stock options, stock appreciation rights, stock awards, restricted stock, restricted stock units and cash incentive awards, under its 2012 Long-Term Incentive Plan (the "Plan"). The Plan was originally approved by stockholders in May 2012 and was amended effective March 8, 2016, to increase the number of shares of common stock authorized for issuance and make certain other changes to the Plan. As of September 30, 2018 , 442,320 shares of common stock were available for issuance under future awards that may be granted under the Plan to employees and directors of, and service providers to, Heartland or its subsidiaries. Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 718, "Compensation-Stock Compensation" requires the measurement of the cost of employee services received in exchange for an award of equity instruments based upon the fair value of the award on the grant date. The cost of the award is based upon its fair value estimated on the date of grant and recognized in the consolidated statements of income over the vesting period of the award. The fair market value of restricted stock and restricted stock units is based on the fair value of the underlying shares of common stock on the date of grant. The fair value of stock options is estimated on the date of grant using the Black-Scholes model. Forfeitures are accounted for as they occur. The amount of tax benefit related to the exercise, vesting and forfeiture of equity-based awards reflected as a tax benefit in Heartland's income tax expense was $672,000 and $1.1 million during the nine months ended September 30, 2018 and 2017, respectively. Restricted Stock Units The Plan permits the Compensation Committee to grant restricted stock units ("RSUs"). In the first quarter of 2018, the Compensation Committee granted time-based RSUs with respect to 52,153 shares of common stock, and in the first quarter of 2017, the Compensation Committee granted time-based RSUs with respect to 55,665 shares of common stock to selected officers and employees. The time-based RSUs represent the right, without payment, to receive shares of Heartland common stock on a specified date in the future. The time-based RSUs granted in 2018 vest over three years in equal installments on March 6 of each of the three years following the year of the grant, while the 2017 time-based RSUs vest in equal installments on January 19 of each of the three years following the year of the grant. The time-based RSUs may also vest upon death or disability, upon a change in control or upon a "qualified retirement" (as defined in the RSU agreement). The retiree is required to sign a non-solicitation agreement as a condition to vesting. In addition to the time-based RSUs referenced in the preceding paragraph, the Compensation Committee granted one -year performance-based RSUs with respect to 18,988 shares of common stock in the first quarter of 2018, and 27,570 shares of common stock in the first quarter of 2017. These performance-based RSUs are earned based on satisfaction of performance targets for the fiscal years ended December 31, 2018, and December 31, 2017, respectively, and then fully vest on a specified date in the third calendar year following the year of the initial grant. The Compensation Committee also granted three -year performance-based RSUs with respect to 16,108 shares and 9,032 shares of common stock in the first quarter of 2018 and 2017, respectively. These performance-based RSUs will be earned based on satisfaction of performance targets for the three -year performance period ended December 31, 2020, and December 31, 2019, respectively. These performance-based RSUs or a portion thereof may vest in 2021 and 2020, respectively, after measurement of performance in relation to the performance targets. The one -year and three -year performance-based RSUs vest to the extent that they are earned upon death or disability or upon a "qualified retirement." Upon a change in control, performance-based RSUs shall become vested at 100% of target if the RSU obligations are not assumed by the successor company. If the successor company does assume the RSU obligations, the 2017 and 2018 performance-based RSUs will vest at 100% of target upon a "Termination of Service" within the period beginning six months prior to a change in control and ending twenty-four months after a change in control. All of Heartland's RSUs will be settled in common stock upon vesting and are not entitled to dividends until vested. The Compensation Committee may grant RSUs under the Plan to directors as part of their compensation, to new management level employees at commencement of employment, and to other employees and service providers as incentives.
Subsequent Events	Heartland has evaluated subsequent events that may require recognition or disclosure through the filing date of this Quarterly Report on Form 10-Q with the SEC.
Effect of New Financial Accounting Standards	In May 2014, the FASB issued Accounting Standards Update ("ASU") 2014-09, " Revenue from Contracts with Customers." The amendment clarifies the principles for recognizing revenue and develops a common revenue standard. The amendment outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that "an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services." In applying the revenue model to contracts within its scope, an entity should apply the following steps: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The new guidance does not apply to certain contracts within the scope of other ASC Topics, such as lease contracts, insurance contracts, financing arrangements, financial instruments, guarantees other than product or service warranties and nonmonetary exchanges between entities in the same line of business to facilitate sales to customers. Heartland evaluates noninterest income contracts affected by the new guidance by analyzing contracts and current accounting practices to determine if a change is appropriate. The amendment is largely consistent with existing guidance and current practices. Heartland adopted the accounting standard effective January 1, 2018, as required, using a modified retrospective approach. However, the adoption of these amendments did not have a significant effect on Heartland's results of operations, financial position and liquidity other than expanded disclosure requirements. See Note 9, "Revenue," for further details regarding Heartland's revenue streams subject to the accounting standard. In January 2016, the FASB issued guidance ASU 2016-01, " Recognition and Measurement of Financial Assets and Financial Liabilitie s." The amendments in ASU 2016-01 to Subtopic 825-10, Financial Instruments, contain the following elements: (1) require equity investments to be measured at fair value with changes in fair value recognized in net income; (2) simplify the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (3) eliminate the requirement for public entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; (4) require public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (5) require an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (6) require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or accompanying notes to the financial statements; and (7) clarify that the entity should evaluate the need for a valuation allowance on a deferred tax asset related to available for sale securities in combination with the entity's other deferred tax assets. The amendments are effective for fiscal years beginning after December 15, 2017, and for interim periods within those fiscal years. Except for the early application of the amendment noted in item (5) above, early adoption of the amendments in this update is not permitted. Entities are required to and Heartland applied the amendment by means of a cumulative-effect adjustment as of the beginning of the fiscal year of adoption, with the exception of the amendment related to equity securities without readily determinable fair values, which is to be applied prospectively to equity investments that exist as of the adoption date. Heartland adopted the accounting standard on January 1, 2018, as required, and the adoption of these amendments did not have a material impact on its results of operations, financial position and liquidity. Heartland reclassified $280,000 from accumulated other comprehensive income to retained earnings on January 1, 2018, related to the fair value of its equity investments. In February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842). " Topic 842 requires a lessee to recognize leases on-balance sheet and disclose key information about leasing arrangements. The new standard establishes a right-of-use model (ROU) that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. Leases will be classified as financing or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The amendment is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and will be applied on a modified retrospective basis. Heartland leases certain properties and equipment under operating leases that will result in recognition of lease assets and lease liabilities on the consolidated balance sheets under the ASU; however the majority of Heartland's properties and equipment are owned, not leased. The modified retrospective approach includes a number of optional practical expedients that entities may elect to apply. These practical expedients relate to the identification and classification of leases that commenced before the effective date, initial direct costs for leases that commenced before the effective date, and the ability to use hindsight in evaluating lessee options to extend or terminate a lease or to purchase the underlying asset. Early adoption is permitted. In January 2018, the FASB issued an amendment to provide entities with the optional practical expedient to not evaluate existing or expired land easements that were previously not accounted for as leases under Topic 840. In July 2018, the FASB issued ASU 2018-11, " Leases - Targeted Improvements " to provide entities with relief from the costs of implementing certain aspects of the new leasing standard, Specifically, under the amendments in ASU 2018-11, entities may elect not to recast the comparative periods presented when transitioning to the new leasing standard, and lessors may elect not to separate lease and non-lease components when certain conditions are met. The amendments have the same effective date as ASU 2016-02. Heartland intends to adopt the accounting standard on January 1, 2019, as required, and will not restate comparative periods. Heartland also expects to adopt certain optional practical expedients. Heartland signed an agreement with a cloud-based lease software provider, and the software implementation is nearly complete. Based on Heartland's current lease portfolio, management anticipates recognizing a right-of-use asset and lease liability on the consolidated balance sheet, with an immaterial impact to the consolidated statement of income. However, the ultimate impact of the standard will depend on the lease portfolio on January 1, 2019. In June 2016, the FASB issued ASU 2016-13, " Financial Instruments - Credit Losses (Topic 326) ." The amendments in this ASU, also referred to as "CECL," require a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. The amendments in this ASU indicate that an entity should not use the length of time a security has been in an unrealized loss position to avoid recording a credit loss. In addition, in determining whether a credit loss exists, the amendments in this ASU also remove the requirements to consider the historical and implied volatility of the fair value of a security and recoveries or declines in fair value after the balance sheet date. The amendment is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. An entity may adopt the amendments earlier as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Heartland intends to adopt the accounting standard in 2020, as required, and expects to recognize a one-time cumulative effect adjustment to the allowance for loan losses as of the beginning of the first reporting period in which the new standard is effective, but cannot yet determine the magnitude of any such one-time adjustment or the overall impact of the new guidance on the results of operations, financial position and liquidity. Heartland has formed a cross-functional internal committee to assess and implement the standard, and the project plan calls for running a parallel CECL model during 2019 prior to adoption in 2020. Heartland has entered into an agreement with a third party software vendor, selected CECL-compliant methodologies, and started implementation of the software. In August 2016, the FASB issued ASU 2016-15, " Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. " The amendments in this update address eight specific cash flow issues with the objective of reducing the existing diversity in practice. The amendment is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes the interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The amendments in this update should be applied using a retrospective transition method to each period presented. Heartland adopted this ASU on January 1, 2018, as required, and the adoption of these amendments did not have a material impact on Heartland's results of operations, financial position and liquidity. In October 2016, the FASB issued ASU 2016-16, "Income Taxes (Topic 740) - Intra-Entity Transfer of Assets Other Than Inventory." The amendment requires an entity to recognize income tax consequences on an intra-entity transfer of an asset other than inventory at the time the transaction occurs. The amendment is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The amendments must be applied and Heartland applied these amendments using a modified retrospective basis. Heartland adopted this ASU on January 1, 2018, as required, and the adoption of this amendment did not have a material impact on Heartland's results of operations, financial position and liquidity. In January 2017, the FASB issued ASU No. 2017-01, " Business Combinations (Topic 805): Clarifying the Definition of a Business ," which narrows the definition of a business and provides a framework that gives entities a basis for making reasonable judgments about whether a transaction involves an asset or a business. ASU 2017-01 is effective for public business entities in annual periods beginning after December 15, 2017, including interim periods therein. Heartland adopted ASU 2017-01 on January 1, 2018, as required, and the adoption did not have a material impact on Heartland's results of operations, financial position, and liquidity. In January 2017, the FASB issued ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350)." This amendment is to simplify the subsequent measurement of goodwill by eliminating step two from the goodwill impairment test. Instead, an entity will perform only step one of its quantitative goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and then recognizing the impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value; however, the loss recognized cannot exceed the total amount of goodwill allocated to that reporting unit. An entity will still have the option to perform a qualitative assessment for a reporting unit to determine if the quantitative step one impairment test is necessary. This amendment is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied prospectively. Early adoption is permitted, including in an interim period for impairment tests performed after January 1, 2017. Heartland intends to adopt this ASU in the third quarter of 2020, consistent with the annual impairment test as of September 30, 2020, and is currently evaluating the potential impact of this guidance on its results of operations, financial position and liquidity. In March 2017, the FASB issued ASU 2017-08, "Receivables - Nonrefundable Fee and Other Costs (Subtopic 310-20)." These amendments shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount. Discounts continue to be amortized to maturity. These amendments are effective for public business entities for fiscal years and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. If any entity early adopts the amendments in an interim period, any adjustments must be reflected as of the beginning of the fiscal year that includes the interim period. The amendments must be applied and Heartland intends to apply these amendments on a modified retrospective basis, with a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Heartland intends to adopt this ASU in 2019, as required, and is currently evaluating the potential impact on its results of operations, financial position and liquidity. In May 2017, the FASB issued ASU 2017-09, " Compensation - Stock Compensation (Topic 718) ." The amendments provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and (3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments are effective for annual periods and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim periods for public business entities for reporting periods for which financial statements have not yet been issued. The amendments should be applied and Heartland applied these amendments prospectively to an award modified on or after the adoption date. Heartland adopted this ASU on January 1, 2018, as required, and the adoption did not have a material impact to its results of operations, financial position and liquidity because Heartland has not typically modified share-based payment awards after the original award has been granted. In August 2017, the FASB issued ASU 2017-12, " Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities ." The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. ASU 2017-12 requires a modified retrospective transition method in which Heartland will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the consolidated balance sheet as of the date of adoption. Heartland intends to adopt this ASU in 2019, as required, and does not believe there will be a material impact to its results of operations, financial position and liquidity. In February 2018, the FASB issued ASU 2018-02, " Income Statement-Reporting Comprehensive Income (Topic 220). " This ASU allows for the option to reclassify from accumulated other comprehensive income ("AOCI") to retained earnings for stranded tax effects resulting from the newly enacted federal corporate income tax rate in the Tax Cuts and Jobs Act of 2017, which was enacted on December 22, 2017. The legislation included a reduction to the corporate income tax rate from 35 percent to 21 percent effective January 1, 2018. The amount of the reclassification would be the difference between the historical corporate income tax rate and the newly enacted 21 percent corporate income tax rate. The amendments in this ASU are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted for public businesses for reporting periods for which financial statements have not yet been issued. Heartland adopted the guidance as of December 31, 2017. The adoption of this ASU was accounted for as a cumulative-effect adjustment to the balance sheet resulting in a $4.5 million increase to retained earnings and a corresponding decrease to AOCI on December 31, 2017. In August 2018, the FASB issued ASU 2018-13, " Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. " This ASU eliminates, adds and modifies certain disclosure requirements for fair value measurements. Among the changes, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy but will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. ASU 2018-13 is effective for interim and annual reporting periods beginning after December 15, 2019, and early adoption is permitted. Heartland intends to adopt this ASU in 2020, as required, and because the ASU only revises disclosure requirements, the adoption of this ASU will not have a material impact on results of operations, financial position and liquidity.
Fair Value Hierarchy	Under ASC 820, assets and liabilities are grouped at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: Level 1 — Valuation is based upon quoted prices for identical instruments in active markets. Level 2 — Valuation is based upon quoted prices for similar instruments in active markets, or similar instruments in markets that are not active, and model-based valuation techniques for all significant assumptions are observable in the market. Level 3 — Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques. The following is a description of valuation methodologies used for assets and liabilities recorded at fair value on a recurring or non-recurring basis. Assets Securities Available for Sale and Held to Maturity Securities available for sale are recorded at fair value on a recurring basis. Securities held to maturity are generally recorded at cost and are recorded at fair value only to the extent a decline in fair value is determined to be other-than-temporary. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security's credit rating, prepayment assumptions and other factors such as credit loss assumptions. Level 1 securities include those traded on an active exchange, such as the New York Stock Exchange, as well as U.S. Treasury securities. Level 2 securities include U.S. government and agency securities, mortgage and asset-backed securities and private collateralized mortgage obligations, municipal bonds and corporate debt securities. On a quarterly basis, a secondary independent pricing service is used for the securities portfolio to validate the pricing from Heartland's primary pricing service. Loans Held for Sale Loans held for sale are carried at the lower of cost or fair value on an aggregate basis. The fair value of loans held for sale is based on what secondary markets are currently offering for portfolios with similar characteristics. As such, Heartland classifies loans held for sale subjected to nonrecurring fair value adjustments as Level 2. Loans Held to Maturity Heartland does not record loans held to maturity at fair value on a recurring basis. However, from time to time, a loan is considered impaired and an allowance for loan losses is established. Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired. Once a loan is identified as individually impaired, management measures impairment in accordance with ASC 310. The fair value of impaired loans is measured using one of the following impairment methods: 1) the present value of expected future cash flows discounted at the loan's effective interest rate or 2) the observable market price of the loan or 3) the fair value of the collateral if the loan is collateral dependent. In accordance with ASC 820, impaired loans measured at fair value are classified as nonrecurring Level 3 in the fair value hierarchy. Premises, Furniture and Equipment Held for Sale Heartland values premises, furniture and equipment held for sale based on third-party appraisals less estimated disposal costs. Heartland considers third party appraisals, as well as independent fair value assessments from Realtors or persons involved in selling bank premises, furniture and equipment, in determining the fair value of particular properties. Accordingly, the valuation of premises, furniture and equipment held for sale is subject to significant external and internal judgment. Heartland periodically reviews premises, furniture and equipment held for sale to determine if the fair value of the property, less disposal costs, has declined below its recorded book value and records any adjustments accordingly. Premises, furniture and equipment held for sale are classified as nonrecurring Level 3 in the fair value hierarchy. Mortgage Servicing Rights Mortgage servicing rights assets represent the value associated with servicing residential real estate loans that have been sold to outside investors with servicing retained. Heartland uses the amortization method (i.e., the lower of amortized cost or estimated fair value measured on a nonrecurring basis), not fair value measurement accounting, to determine the carrying value of its mortgage servicing rights. The fair value for servicing assets is determined through discounted cash flow analysis and utilizes discount rates, prepayment speeds and delinquency rate assumptions as inputs. All of the assumptions in the discounted cash flow analysis require a significant degree of management estimation and judgment. Mortgage servicing rights are subject to impairment testing. The carrying values of these rights are reviewed quarterly for impairment based upon the calculation of fair value as performed by an outside third party. For purposes of measuring impairment, the rights are stratified into certain risk characteristics including note type and note term. If the valuation model reflects a fair value less than the carrying value, mortgage servicing rights are adjusted to fair value through a valuation allowance. Heartland classifies mortgage servicing rights as nonrecurring with Level 3 measurement inputs. Commercial Servicing Rights Commercial servicing rights assets represent the value associated with servicing commercial loans guaranteed by the Small Business Administration and the United States Department of Agriculture that have been sold with servicing retained by Heartland. Heartland uses the amortization method (i.e., the lower of amortized cost or estimated fair value measured on a nonrecurring basis), not fair value measurement accounting, to determine the carrying value of its commercial servicing rights. The fair value for servicing assets is determined through market prices for comparable servicing contracts, when available, or through a valuation model that calculates the present value of estimated future net servicing income. Inputs utilized include discount rates, prepayment speeds and delinquency rate assumptions as inputs. All of these assumptions require a significant degree of management estimation and judgment. Commercial servicing rights are subject to impairment testing, and the carrying values of these rights are reviewed quarterly for impairment based upon the calculation of fair value as performed by an outside third party. If the valuation model reflects a fair value less than the carrying value, commercial servicing rights are adjusted to fair value through a valuation allowance. Heartland classifies commercial servicing rights as nonrecurring with Level 3 measurement inputs. Derivative Financial Instruments Heartland's current interest rate risk strategy includes interest rate swaps. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. To comply with the provisions of ASC 820, Heartland incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty's nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, Heartland has considered the impact of netting any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although Heartland has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of September 30, 2018 , and December 31, 2017 , Heartland has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, Heartland has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. Interest rate lock commitments Heartland uses an internal valuation model that relies on internally developed inputs to estimate the fair value of its interest rate lock commitments which is based on unobservable inputs that reflect management's assumptions and specific information about each borrower. Interest rate lock commitments are classified in Level 3 of the fair value hierarchy. Forward commitments The fair value of forward commitments are estimated using an internal valuation model, which includes current trade pricing for similar financial instruments in active markets that Heartland has the ability to access and are classified in Level 2 of the fair value hierarchy. Other Real Estate Owned Other real estate owned ("OREO") represents property acquired through foreclosures and settlements of loans. Property acquired is carried at the fair value of the property at the time of acquisition (representing the property's cost basis), plus any acquisition costs, or the estimated fair value of the property, less disposal costs. Heartland considers third party appraisals, as well as independent fair value assessments from realtors or persons involved in selling OREO, in determining the fair value of particular properties. Accordingly, the valuation of OREO is subject to significant external and internal judgment. Heartland periodically reviews OREO to determine if the fair value of the property, less disposal costs, has declined below its recorded book value and records any adjustments accordingly. OREO is classified as nonrecurring Level 3 of the fair value hierarchy.
Revenue Recognition	Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity’s obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. Heartland's noninterest revenue streams are largely based on transactional activity, or standard month-end revenue accruals such as asset management fees based on month-end market values. Consideration is often received immediately or shortly after Heartland satisfies its performance obligation and revenue is recognized. Heartland does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of September 30, 2018, and December 31, 2017, Heartland did not have any significant contract balances. Contract Acquisition Costs In connection with the adoption of Topic 606, an entity is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained (for example, sales commission). Heartland utilizes the practical expedient which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, Heartland did not capitalize any contract acquisition costs.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Amounts used in the determination of basic and diluted earnings per share for the three- and nine- month periods ended September 30, 2018 , and 2017 , are shown in the table below: Three Months Ended (Dollars and number of shares in thousands, except per share data) 2018 2017 Net income $ 33,710 $ 21,632 Preferred dividends (13 ) (13 ) Interest expense on convertible preferred debt — 3 Net income available to common stockholders $ 33,697 $ 21,622 Weighted average common shares outstanding for basic earnings per share 34,452 29,648 Assumed incremental common shares issued upon vesting of outstanding restricted stock units 192 262 Weighted average common shares for diluted earnings per share 34,644 29,910 Earnings per common share — basic $ 0.98 $ 0.73 Earnings per common share — diluted $ 0.97 $ 0.72 Number of antidilutive common stock equivalents excluded from diluted earnings per share computation — — Nine Months Ended (Dollars and number of shares in thousands, except per share data) 2018 2017 Net income $ 84,857 $ 61,600 Preferred dividends (39 ) (45 ) Interest expense on convertible preferred debt — 12 Net income available to common stockholders $ 84,818 $ 61,567 Weighted average common shares outstanding for basic earnings per share 32,520 27,569 Assumed incremental common shares issued upon vesting of outstanding restricted stock units 187 265 Weighted average common shares for diluted earnings per share 32,707 27,834 Earnings per common share — basic $ 2.61 $ 2.23 Earnings per common share — diluted $ 2.59 $ 2.21 Number of antidilutive common stock equivalents excluded from diluted earnings per share computation — —
Summary of Status of RSUs	A summary of the RSUs outstanding as of September 30, 2018 , and 2017 , and changes during the nine months ended September 30, 2018 and 2017 , follows: 2018 2017 Shares Weighted-Average Grant Date Fair Value Shares Weighted-Average Grant Date Fair Value Outstanding at January 1 301,578 $ 34.74 346,817 $ 27.61 Granted 116,297 55.26 109,071 47.21 Vested (127,429 ) 32.70 (136,428 ) 26.66 Forfeited (27,678 ) 45.58 (12,923 ) 31.57 Outstanding at September 30 262,768 $ 43.65 306,537 $ 34.72
Summary of Status of Stock Options	A summary of the stock options outstanding as of September 30, 2018 and 2017 , and changes during the nine months ended September 30, 2018 and 2017 , follows: 2018 2017 Shares Weighted-Average Exercise Price Shares Weighted-Average Exercise Price Outstanding at January 1 6,500 $ 18.60 26,400 $ 18.60 Granted — — — — Exercised (6,500 ) 18.60 (13,650 ) 18.60 Forfeited — — (500 ) 18.60 Outstanding at September 30 — $ — 12,250 $ 18.60 Options exercisable at September 30 — $ — 12,250 $ 18.60

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table represents, in thousands, the amounts recorded on the consolidated balance sheet as of May 18, 2018: As of May 18, 2018 Fair value of consideration paid: Common stock (3,350,664 shares) $ 184,454 Cash 5,451 Total consideration paid 189,905 Fair value of assets acquired Cash and cash equivalents 212,105 Securities: Carried at fair value 1,788 Other securities 3,268 Loans held for sale 31,050 Loans held to maturity 681,080 Premises, furniture and equipment, net 23,271 Other real estate, net 379 Mortgage servicing rights 6,995 Core deposit intangibles and customer relationships, net 13,908 Cash surrender value on life insurance 14,997 Other assets 7,185 Total assets 996,026 Fair value of liabilities assumed Deposits 893,827 Other borrowings 12,077 Other liabilities 21,580 Total liabilities assumed 927,484 Fair value of net assets acquired 68,542 Goodwill resulting from acquisition $ 121,363
Summary of Pro Forma Information	The following pro forma information represents the results of operations for the nine-month periods ended September 30, 2018, and 2017, as if the FBLB acquisition occurred on January 1, 2018, and January 1, 2017, respectively: (Dollars in thousands, except per share data), unaudited For the Nine Months Ended September 30, 2018 September 30, 2017 Net interest income $ 317,846 $ 262,367 Net income available to common stockholders $ 69,075 $ 76,698 Basic earnings per share $ 2.02 $ 2.48 Diluted earnings per share $ 2.01 $ 2.46

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of Available for Sale Securities	The amortized cost, gross unrealized gains and losses, and estimated fair values of debt securities available for sale and equity securities with a readily determinable that are carried at fair value as of September 30, 2018 , and December 31, 2017 , are summarized in the table below, in thousands: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value September 30, 2018 U.S. government corporations and agencies $ 27,112 $ — $ (115 ) $ 26,997 Mortgage and asset-backed securities 1,926,803 1,341 (56,325 ) 1,871,819 Obligations of states and political subdivisions 372,146 239 (13,902 ) 358,483 Total debt securities 2,326,061 1,580 (70,342 ) 2,257,299 Equity securities with a readily determinable fair value 16,916 — — 16,916 Total $ 2,342,977 $ 1,580 $ (70,342 ) $ 2,274,215 December 31, 2017 U.S. government corporations and agencies $ 5,358 $ 8 $ (38 ) $ 5,328 Mortgage and asset-backed securities 1,785,467 5,856 (37,587 ) 1,753,736 Obligations of states and political subdivisions 441,060 4,669 (4,714 ) 441,015 Total debt securities 2,231,885 10,533 (42,339 ) 2,200,079 Equity securities 16,296 378 — 16,674 Total $ 2,248,181 $ 10,911 $ (42,339 ) $ 2,216,753
Schedule of Held to Maturity Securities	The amortized cost, gross unrealized gains and losses and estimated fair values of held to maturity securities as of September 30, 2018 , and December 31, 2017 , are summarized in the table below, in thousands: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value September 30, 2018 Obligations of states and political subdivisions $ 239,908 $ 8,422 $ (936 ) $ 247,394 Total $ 239,908 $ 8,422 $ (936 ) $ 247,394 December 31, 2017 Obligations of states and political subdivisions $ 253,550 $ 12,460 $ (516 ) $ 265,494 Total $ 253,550 $ 12,460 $ (516 ) $ 265,494
Investments Classified by Contractual Maturity Date	The amortized cost and estimated fair value of investment securities carried at fair value at September 30, 2018 , by contractual maturity, are as follows, in thousands. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without penalties. September 30, 2018 Amortized Cost Estimated Fair Value Due in 1 year or less $ 23,216 $ 23,161 Due in 1 to 5 years 50,520 49,592 Due in 5 to 10 years 131,431 125,824 Due after 10 years 194,091 186,903 Total debt securities 399,258 385,480 Mortgage and asset-backed securities 1,926,803 1,871,819 Equity securities with a readily determinable fair value 16,916 16,916 Total investment securities $ 2,342,977 $ 2,274,215 The amortized cost and estimated fair value of debt securities held to maturity at September 30, 2018 , by contractual maturity, are as follows, in thousands. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without penalties. September 30, 2018 Amortized Cost Estimated Fair Value Due in 1 year or less $ 1,274 $ 1,281 Due in 1 to 5 years 31,121 31,495 Due in 5 to 10 years 105,183 107,052 Due after 10 years 102,330 107,566 Total investment securities $ 239,908 $ 247,394
Schedule of Realized Gross Gains (Losses)	Gross gains and losses realized related to the sales of securities carried at fair value for the three- and nine- month periods ended September 30, 2018 and 2017 , are summarized as follows, in thousands: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Proceeds from sales $ 59,137 $ 503,083 $ 694,872 $ 1,127,091 Gross security gains 67 2,088 3,537 8,585 Gross security losses 212 409 2,500 3,023
Schedule of Debt Securities Available-for-sale	The following tables summarize, in thousands, the amount of unrealized losses, defined as the amount by which cost or amortized cost exceeds fair value, and the related fair value of investments with unrealized losses in Heartland's securities portfolio as of September 30, 2018 , and December 31, 2017 . The investments were segregated into two categories: those that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 months or more. The reference point for determining how long an investment was in an unrealized loss position w as September 30, 2017 , and December 31, 2016 , respectively. Securities for which Heartland has taken credit-related other-than-temporary impairment ("OTTI") write-downs are categorized as being "less than 12 months" or "12 months or longer" in a continuous loss position based on the point in time that the fair value declined to below the cost basis and not the period of time since the credit-related OTTI write-down. Debt securities available for sale Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses September 30, 2018 U.S. government corporations and agencies $ 22,392 $ (39 ) $ 4,605 $ (76 ) $ 26,997 $ (115 ) Mortgage and asset-backed securities 1,007,078 (18,299 ) 668,623 (38,026 ) 1,675,701 (56,325 ) Obligations of states and political subdivisions 203,363 (5,552 ) 139,394 (8,350 ) 342,757 (13,902 ) Total temporarily impaired securities $ 1,232,833 $ (23,890 ) $ 812,622 $ (46,452 ) $ 2,045,455 $ (70,342 ) December 31, 2017 U.S. government corporations and agencies $ 4,819 $ (38 ) $ — $ — $ 4,819 $ (38 ) Mortgage and asset-backed securities 851,070 (11,533 ) 399,978 (26,054 ) 1,251,048 (37,587 ) Obligations of states and political subdivisions 93,040 (667 ) 159,180 (4,047 ) 252,220 (4,714 ) Total temporarily impaired securities $ 948,929 $ (12,238 ) $ 559,158 $ (30,101 ) $ 1,508,087 $ (42,339 )
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	Securities held to maturity Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses September 30, 2018 Obligations of states and political subdivisions $ 29,174 $ (209 ) $ 13,160 $ (727 ) $ 42,334 $ (936 ) Total temporarily impaired securities $ 29,174 $ (209 ) $ 13,160 $ (727 ) $ 42,334 $ (936 ) December 31, 2017 Obligations of states and political subdivisions $ 8,512 $ (49 ) $ 8,989 $ (467 ) $ 17,501 $ (516 ) Total temporarily impaired securities $ 8,512 $ (49 ) $ 8,989 $ (467 ) $ 17,501 $ (516 )

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Schedule of Loans	Loans as of September 30, 2018 , and December 31, 2017 , were as follows, in thousands: September 30, 2018 December 31, 2017 Loans receivable held to maturity: Commercial $ 1,962,222 $ 1,646,606 Commercial real estate 3,648,731 3,163,269 Agricultural and agricultural real estate 574,048 511,588 Residential real estate 676,941 624,279 Consumer 506,181 447,484 Gross loans receivable held to maturity 7,368,123 6,393,226 Unearned discount (1,340 ) (556 ) Deferred loan fees (1,290 ) (1,206 ) Total net loans receivable held to maturity 7,365,493 6,391,464 Allowance for loan losses (61,221 ) (55,686 ) Loans receivable, net $ 7,304,272 $ 6,335,778
Allowance for Loan and Lease Losses, Based on Impairment Methodology	The following table shows the balance in the allowance for loan losses at September 30, 2018 , and December 31, 2017 , and the related loan balances, disaggregated on the basis of impairment methodology, in thousands. Loans evaluated under ASC 310-10-35 include loans on nonaccrual status and troubled debt restructurings, which are individually evaluated for impairment, and other impaired loans deemed to have similar risk characteristics. All other loans are collectively evaluated for impairment under ASC 450-20. Heartland has made no significant changes to the accounting for the allowance for loan losses during 2018. Allowance For Loan Losses Gross Loans Receivable Held to Maturity Ending Balance Under ASC 310-10-35 Ending Balance Under ASC 450-20 Total Ending Balance Evaluated for Impairment Under ASC 310-10-35 Ending Balance Evaluated for Impairment Under ASC 450-20 Total September 30, 2018 Commercial $ 4,165 $ 17,904 $ 22,069 $ 23,414 $ 1,938,808 $ 1,962,222 Commercial real estate 214 23,476 23,690 14,415 3,634,316 3,648,731 Agricultural and agricultural real estate 260 4,306 4,566 17,522 556,526 574,048 Residential real estate 279 1,571 1,850 23,647 653,294 676,941 Consumer 1,085 7,961 9,046 8,671 497,510 506,181 Total $ 6,003 $ 55,218 $ 61,221 $ 87,669 $ 7,280,454 $ 7,368,123 December 31, 2017 Commercial $ 1,613 $ 16,485 $ 18,098 $ 7,415 $ 1,639,191 $ 1,646,606 Commercial real estate 766 21,184 21,950 23,705 3,139,564 3,163,269 Agricultural and agricultural real estate 546 3,712 4,258 13,304 498,284 511,588 Residential real estate 430 1,794 2,224 27,141 597,138 624,279 Consumer 1,400 7,756 9,156 6,903 440,581 447,484 Total $ 4,755 $ 50,931 $ 55,686 $ 78,468 $ 6,314,758 $ 6,393,226
Schedule of Financing Receivables, Non Accrual Status	The following table presents nonaccrual loans, accruing loans past due 90 days or more and performing troubled debt restructured loans at September 30, 2018 , and December 31, 2017 , in thousands: September 30, 2018 December 31, 2017 Nonaccrual loans $ 68,528 $ 58,272 Nonaccrual troubled debt restructured loans 4,532 4,309 Total nonaccrual loans $ 73,060 $ 62,581 Accruing loans past due 90 days or more $ 154 $ 830 Performing troubled debt restructured loans $ 4,180 $ 6,617
Troubled Debt Restructuring on Loans Modified	The following tables provide information on troubled debt restructured loans that were modified during the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , dollars in thousands: Three Months Ended 2018 2017 Number Pre- Post- Number Pre- Post- Commercial — $ — $ — — $ — $ — Commercial real estate — — — — — — Total commercial and commercial real estate — — — — — — Agricultural and agricultural real estate — — — — — — Residential real estate 1 92 94 8 1,174 1,174 Consumer — — — — — — Total 1 $ 92 $ 94 8 $ 1,174 $ 1,174 Nine Months Ended 2018 2017 Number of Loans Pre- Modification Recorded Investment Post- Modification Recorded Investment Number of Loans Pre- Modification Recorded Investment Post- Modification Recorded Investment Commercial — $ — $ — 3 $ 131 $ 131 Commercial real estate — — — — — — Total commercial and commercial real estate — — — 3 131 131 Agricultural and agricultural real estate — — — — — — Residential real estate 11 2,098 1,808 22 2,977 2,977 Consumer — — — — — — Total 11 $ 2,098 $ 1,808 25 $ 3,108 $ 3,108 The following table shows troubled debt restructured loans for which there was a payment default during the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , that had been modified during the twelve-month period prior to default, in thousands: With Payment Defaults During the Three Months Ended September 30, 2018 2017 Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial — $ — — $ — Commercial real estate — — — — Total commercial and commercial real estate — — — — Agricultural and agricultural real estate — — — — Residential real estate 4 418 5 1,221 Consumer — — — — Total 4 $ 418 5 $ 1,221 With Payment Defaults During the Nine Months Ended September 30, 2018 2017 Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial — $ — — $ — Commercial real estate — — — — Total commercial and commercial real estate — — — — Agricultural and agricultural real estate — — — — Residential real estate 10 1,598 8 1,480 Consumer — — — — Total 10 $ 1,598 8 $ 1,480
Financing Receivable Credit Quality Indicators	The following table presents loans by credit quality indicator at September 30, 2018 , and December 31, 2017 , in thousands: Pass Nonpass Total September 30, 2018 Commercial $ 1,825,692 $ 136,530 $ 1,962,222 Commercial real estate 3,467,522 181,209 3,648,731 Total commercial and commercial real estate 5,293,214 317,739 5,610,953 Agricultural and agricultural real estate 476,261 97,787 574,048 Residential real estate 644,592 32,349 676,941 Consumer 491,092 15,089 506,181 Total gross loans receivable held to maturity $ 6,905,159 $ 462,964 $ 7,368,123 December 31, 2017 Commercial $ 1,552,783 $ 93,823 $ 1,646,606 Commercial real estate 2,985,501 177,768 3,163,269 Total commercial and commercial real estate 4,538,284 271,591 4,809,875 Agricultural and agricultural real estate 451,539 60,049 511,588 Residential real estate 586,623 37,656 624,279 Consumer 432,936 14,548 447,484 Total gross loans receivable held to maturity $ 6,009,382 $ 383,844 $ 6,393,226
Past Due Financing Receivables	The following table sets forth information regarding Heartland's accruing and nonaccrual loans at September 30, 2018 , and December 31, 2017 , in thousands: Accruing Loans 30-59 Days Past Due 60-89 Days 90 Days or More Past Due Total Past Due Current Nonaccrual Total Loans September 30, 2018 Commercial $ 10,558 $ 3,521 $ 61 $ 14,140 $ 1,924,173 $ 23,909 $ 1,962,222 Commercial real estate 11,495 9,036 58 20,589 3,616,737 11,405 3,648,731 Total commercial and commercial real estate 22,053 12,557 119 34,729 5,540,910 35,314 5,610,953 Agricultural and agricultural real estate 1,294 1,146 35 2,475 554,055 17,518 574,048 Residential real estate 2,893 192 — 3,085 659,662 14,194 676,941 Consumer 4,493 811 — 5,304 494,843 6,034 506,181 Total gross loans receivable held to maturity $ 30,733 $ 14,706 $ 154 $ 45,593 $ 7,249,470 $ 73,060 $ 7,368,123 December 31, 2017 Commercial $ 1,246 $ 259 $ 100 $ 1,605 $ 1,637,773 $ 7,228 $ 1,646,606 Commercial real estate 4,769 2,326 — 7,095 3,139,576 16,598 3,163,269 Total commercial and commercial real estate 6,015 2,585 100 8,700 4,777,349 23,826 4,809,875 Agricultural and agricultural real estate 604 134 — 738 497,546 13,304 511,588 Residential real estate 2,022 270 — 2,292 601,120 20,867 624,279 Consumer 4,734 943 730 6,407 436,493 4,584 447,484 Total gross loans receivable held to maturity $ 13,375 $ 3,932 $ 830 $ 18,137 $ 6,312,508 $ 62,581 $ 6,393,226
Summary of Impaired Loans	The following tables present, by category of loan, impaired loans, the unpaid contractual loan balances at September 30, 2018 , and December 31, 2017 ; the outstanding loan balances recorded on the consolidated balance sheets at September 30, 2018 , and December 31, 2017 ; any related allowance recorded for those loans as of September 30, 2018 , and December 31, 2017 ; the average outstanding loan balances recorded on the consolidated balance sheets during the three- and nine- months ended September 30, 2018 , and year ended December 31, 2017 ; and the interest income recognized on the impaired loans during the three- and nine- month periods ended September 30, 2018 , and year ended December 31, 2017 , in thousands: Unpaid Contractual Balance Loan Balance Related Allowance Recorded Quarter- to- Date Avg. Loan Balance Quarter- to- Date Interest Income Recognized Year- to- Date Avg. Loan Balance Year- to- Date Interest Income Recognized September 30, 2018 Impaired loans with a related allowance: Commercial $ 6,768 $ 6,768 $ 4,165 $ 5,173 $ 16 $ 3,593 $ 52 Commercial real estate 748 748 214 889 4 5,635 20 Total commercial and commercial real estate 7,516 7,516 4,379 6,062 20 9,228 72 Agricultural and agricultural real estate 2,043 2,043 260 3,000 2 2,369 2 Residential real estate 869 869 279 1,006 4 1,278 10 Consumer 3,028 3,028 1,085 3,146 9 3,069 29 Total impaired loans with a related allowance $ 13,456 $ 13,456 $ 6,003 $ 13,214 $ 35 $ 15,944 $ 113 Impaired loans without a related allowance: Commercial $ 18,003 $ 16,646 $ — $ 13,113 $ 182 $ 9,307 $ 277 Commercial real estate 13,765 13,667 — 11,850 80 12,847 201 Total commercial and commercial real estate 31,768 30,313 — 24,963 262 22,154 478 Agricultural and agricultural real estate 18,002 15,479 — 15,837 1 14,726 4 Residential real estate 22,778 22,778 — 22,779 121 24,780 320 Consumer 5,643 5,643 — 5,522 22 4,930 78 Total impaired loans without a related allowance $ 78,191 $ 74,213 $ — $ 69,101 $ 406 $ 66,590 $ 880 Total impaired loans held to maturity: Commercial $ 24,771 $ 23,414 $ 4,165 $ 18,286 $ 198 $ 12,900 $ 329 Commercial real estate 14,513 14,415 214 12,739 84 18,482 221 Total commercial and commercial real estate 39,284 37,829 4,379 31,025 282 31,382 550 Agricultural and agricultural real estate 20,045 17,522 260 18,837 3 17,095 6 Residential real estate 23,647 23,647 279 23,785 125 26,058 330 Consumer 8,671 8,671 1,085 8,668 31 7,999 107 Total impaired loans held to maturity $ 91,647 $ 87,669 $ 6,003 $ 82,315 $ 441 $ 82,534 $ 993 Unpaid Contractual Balance Loan Balance Related Allowance Recorded Year-to- Date Avg. Loan Balance Year-to- Date Interest Income Recognized December 31, 2017 Impaired loans with a related allowance: Commercial $ 2,292 $ 2,292 $ 1,613 $ 3,607 $ 39 Commercial real estate 11,925 10,068 766 11,479 34 Total commercial and commercial real estate 14,217 12,360 2,379 15,086 73 Agricultural and agricultural real estate 1,539 1,539 546 3,437 — Residential real estate 1,568 1,568 430 2,056 15 Consumer 2,634 2,634 1,400 2,370 41 Total impaired loans with a related allowance $ 19,958 $ 18,101 $ 4,755 $ 22,949 $ 129 Impaired loans without a related allowance: Commercial $ 6,243 $ 5,123 $ — $ 2,586 $ 165 Commercial real estate 14,243 13,637 — 20,148 514 Total commercial and commercial real estate 20,486 18,760 — 22,734 679 Agricultural and agricultural real estate 13,793 11,765 — 9,654 — Residential real estate 25,573 25,573 — 26,024 277 Consumer 4,269 4,269 — 3,884 73 Total impaired loans without a related allowance $ 64,121 $ 60,367 $ — $ 62,296 $ 1,029 Total impaired loans held to maturity: Commercial $ 8,535 $ 7,415 $ 1,613 $ 6,193 $ 204 Commercial real estate 26,168 23,705 766 31,627 548 Total commercial and commercial real estate 34,703 31,120 2,379 37,820 752 Agricultural and agricultural real estate 15,332 13,304 546 13,091 — Residential real estate 27,141 27,141 430 28,080 292 Consumer 6,903 6,903 1,400 6,254 114 Total impaired loans held to maturity $ 84,079 $ 78,468 $ 4,755 $ 85,245 $ 1,158 At September 30, 2018 , and December 31, 2017 , the carrying amount of loans acquired since 2015 consist of purchased impaired and nonimpaired loans as summarized in the following table, in thousands: September 30, 2018 December 31, 2017 Impaired Non Impaired Total Loans Impaired Non Impaired Total Loans Commercial $ 9,078 $ 300,261 $ 309,339 $ 952 $ 187,375 $ 188,327 Commercial real estate 302 1,202,537 1,202,839 2,572 1,052,469 1,055,041 Agricultural and agricultural real estate — 32,357 32,357 — 1,242 1,242 Residential real estate 220 204,414 204,634 214 173,909 174,123 Consumer loans — 89,061 89,061 — 51,292 51,292 Total loans $ 9,600 $ 1,828,630 $ 1,838,230 $ 3,738 $ 1,466,287 $ 1,470,025
Changes in Accretable Yield on Acquired Loans	Changes in accretable yield on acquired loans with evidence of credit deterioration at the date of acquisition for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , were as follows, in thousands: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Balance at beginning of period $ 463 $ 101 $ 57 $ 182 Original yield discount, net, at date of acquisition — — 508 — Accretion (93 ) (700 ) (943 ) (1,074 ) Reclassification from nonaccretable difference (1) 186 654 934 947 Balance at period end $ 556 $ 55 $ 556 $ 55 (1) Represents increases in estimated cash flows expected to be received, primarily due to lower estimated credit losses.

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2018
Loans and Leases Receivable Disclosure [Abstract]
Changes in the Allowance for Loan and Leases Losses	Changes in the allowance for loan losses for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , were as follows, in thousands: Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at June 30, 2018 $ 20,709 $ 23,727 $ 5,709 $ 1,857 $ 9,322 $ 61,324 Charge-offs (2,945 ) (199 ) (1,145 ) — (1,831 ) (6,120 ) Recoveries 158 242 — 1 378 779 Provision 4,147 (80 ) 2 (8 ) 1,177 5,238 Balance at September 30, 2018 $ 22,069 $ 23,690 $ 4,566 $ 1,850 $ 9,046 $ 61,221 Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at December 31, 2017 $ 18,098 $ 21,950 $ 4,258 $ 2,224 $ 9,156 $ 55,686 Charge-offs (4,717 ) (761 ) (1,357 ) (211 ) (4,462 ) (11,508 ) Recoveries 562 1,013 14 77 1,045 2,711 Provision 8,126 1,488 1,651 (240 ) 3,307 14,332 Balance at September 30, 2018 $ 22,069 $ 23,690 $ 4,566 $ 1,850 $ 9,046 $ 61,221 Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at June 30, 2017 $ 17,168 $ 21,861 $ 3,832 $ 2,263 $ 8,927 $ 54,051 Charge-offs (1,954 ) (1,913 ) — (142 ) (1,750 ) (5,759 ) Recoveries 347 46 14 63 418 888 Provision 1,409 546 2,281 82 1,387 5,705 Balance at September 30, 2017 $ 16,970 $ 20,540 $ 6,127 $ 2,266 $ 8,982 $ 54,885 Commercial Commercial Real Estate Agricultural and Agricultural Real Estate Residential Real Estate Consumer Total Balance at December 31, 2016 $ 14,765 $ 24,319 $ 4,210 $ 2,263 $ 8,767 $ 54,324 Charge-offs (3,310 ) (2,522 ) (888 ) (541 ) (4,982 ) (12,243 ) Recoveries 635 860 17 70 987 2,569 Provision 4,880 (2,117 ) 2,788 474 4,210 10,235 Balance at September 30, 2017 $ 16,970 $ 20,540 $ 6,127 $ 2,266 $ 8,982 $ 54,885

Goodwill, Core Deposit Premiu_2

Goodwill, Core Deposit Premium and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Gross Carrying Amount and Accumulated Amortization of Other Intangible Assets	The gross carrying amount of these intangible assets and the associated accumulated amortization at September 30, 2018 , and December 31, 2017 , are presented in the table below, in thousands: September 30, 2018 December 31, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Amortizing intangible assets: Core deposit intangibles $ 83,639 $ 33,820 $ 49,819 $ 62,008 $ 27,086 $ 34,922 Customer relationship intangibles 1,177 925 252 1,177 896 281 Mortgage servicing rights 42,616 12,445 30,171 42,139 18,891 23,248 Commercial servicing rights 6,800 4,932 1,868 6,719 4,110 2,609 Total $ 134,232 $ 52,122 $ 82,110 $ 112,043 $ 50,983 $ 61,060
Schedule of Estimated Future Amortization Expense of Amortizable Intangible Assets	The following table shows the estimated future amortization expense for amortizable intangible assets, in thousands: Core Deposit Intangibles Customer Relationship Intangibles Mortgage Servicing Rights Commercial Servicing Rights Total Three months ending December 31, 2018 $ 2,583 $ 10 $ 1,642 $ 139 $ 4,374 Year ending December 31, 2019 9,452 38 7,132 485 17,107 2020 8,230 37 6,113 379 14,759 2021 7,036 35 5,094 331 12,496 2022 5,634 34 4,076 270 10,014 2023 4,933 34 3,057 154 8,178 Thereafter 11,951 64 3,057 110 15,182 Total $ 49,819 $ 252 $ 30,171 $ 1,868 $ 82,110
Summary of Changes in Servicing Rights	The following table summarizes, in thousands, the changes in capitalized mortgage servicing rights for the nine months ended September 30, 2018 , and September 30, 2017 : 2018 2017 Balance at January 1, $ 23,248 $ 32,088 Originations 4,322 5,778 Amortization (4,394 ) (7,184 ) Valuation allowance on mortgage servicing rights — — Sale of mortgage servicing rights — (6,940 ) Acquired mortgage servicing rights 6,995 — Balance at period end $ 30,171 $ 23,742 Fair value of mortgage servicing rights $ 47,581 $ 35,002 Mortgage servicing rights, net to servicing portfolio 0.73 % 0.67 % The following table summarizes, in thousands, the changes in capitalized commercial servicing rights for the nine -months ended September 30, 2018 , and September 30, 2017 : 2018 2017 Balance at January 1, $ 2,609 $ 3,690 Originations 82 215 Amortization (835 ) (1,077 ) Valuation allowance on commercial servicing rights 12 29 Balance at period end $ 1,868 $ 2,857 Fair value of commercial servicing rights $ 2,529 $ 3,458 Commercial servicing rights, net to servicing portfolio 1.63 % 1.98 %
Schedule of Servicing Asset at Fair Value and Amortized Cost	The following table summarizes, in thousands, the book value, the fair value of each tranche of the mortgage servicing rights and any recorded valuation allowance at each respective subsidiary at September 30, 2018 , and December 31, 2017 : September 30, 2018 Book Value 15-Year Tranche Fair Value 15-Year Tranche Impairment 15-Year Tranche Book Value 30-Year Tranche Fair Value 30-Year Tranche Impairment 30-Year Tranche Dubuque Bank and Trust Company $ 2,371 $ 4,747 $ — $ 20,632 $ 35,610 $ — First Bank & Trust 1,685 1,741 — 5,483 5,483 — Total $ 4,056 $ 6,488 $ — $ 26,115 $ 41,093 $ — December 31, 2017 Dubuque Bank and Trust Company $ 2,858 $ 4,988 $ — $ 20,390 $ 32,093 $ — Total $ 2,858 $ 4,988 $ — $ 20,390 $ 32,093 $ — The following table summarizes, in thousands, the book value, the fair value of each tranche of the commercial servicing rights and any recorded valuation allowance at each respective subsidiary at September 30, 2018 , and December 31, 2017 : September 30, 2018 Book Value Less than 20 Years Fair Value Less than 20 Years Impairment Less than 20 Years Book Value More than 20 Years Fair Value More than 20 Years Impairment More than 20 Years Citywide Banks $ 2 $ 6 $ — $ 30 $ 33 $ — Premier Valley Bank 53 82 — 188 203 — Wisconsin Bank & Trust 260 519 — 1,335 1,686 — Total $ 315 $ 607 $ — $ 1,553 $ 1,922 $ — December 31, 2017 Citywide Banks $ 8 $ 11 $ — $ 34 $ 37 $ — Premier Valley Bank 83 110 — 303 291 12 Wisconsin Bank & Trust 446 619 — 1,747 2,153 — Total $ 537 $ 740 $ — $ 2,084 $ 2,481 $ 12

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Balance Sheet Category and Fair Values of Derivative Instruments	The table below identifies the balance sheet category and fair values of Heartland's derivative instruments designated as cash flow hedges at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category Receive Rate Weighted Average Pay Rate Maturity September 30, 2018 Interest rate swap $ 25,000 $ 424 Other assets 2.334 % 2.255 % 03/17/2021 Interest rate swap 20,000 (186 ) Other liabilities 2.339 3.355 01/07/2020 Interest rate swap 10,000 42 Other assets 2.374 1.674 03/26/2019 Interest rate swap 10,000 42 Other assets 2.334 1.658 03/18/2019 Interest rate swap 30,667 1,089 Other assets 4.633 3.674 05/10/2021 Interest rate swap 29,500 (33 ) Other liabilities 4.712 5.425 07/24/2028 Interest rate swap 20,000 652 Other assets 2.334 2.390 06/15/2024 Interest rate swap 20,000 666 Other assets 2.321 2.352 03/01/2024 Interest rate swap 6,000 175 Other assets 2.334 1.866 06/15/2021 Interest rate swap 3,000 92 Other assets 2.436 1.878 06/30/2021 December 31, 2017 Interest rate swap $ 25,000 $ (106 ) Other liabilities 1.600 % 2.255 % 03/17/2021 Interest rate swap 20,000 (621 ) Other liabilities 1.350 3.355 01/07/2020 Interest rate swap 10,000 30 Other assets 1.329 1.674 03/26/2019 Interest rate swap 10,000 29 Other assets 1.600 1.658 03/18/2019 Interest rate swap 33,667 759 Other assets 3.932 3.674 05/10/2021 Interest rate swap 20,000 (177 ) Other liabilities 1.588 2.390 06/15/2024 Interest rate swap 20,000 (149 ) Other Liabilities 1.481 2.352 03/01/2024 The table below identifies the balance sheet category and fair values of Heartland's derivative instruments designated as loan swaps at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category Weighted Average Receive Rate Weighted Average Pay Rate September 30, 2018 Customer interest rate swaps $ 200,241 $ 5,305 Other assets 5.07 % 4.68 % Customer interest rate swaps 200,241 (5,305 ) Other liabilities 4.68 5.07 December 31, 2017 Customer interest rate swaps $ 126,766 $ 2,377 Other assets 4.70 % 4.03 % Customer interest rate swaps 126,766 (2,377 ) Other liabilities 4.03 4.70 The table below identifies the notional amount, fair value and balance sheet category of Heartland's fair value hedges at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category September 30, 2018 Fair value hedges $ 30,954 $ 625 Other assets Fair value hedges 4,133 (201 ) Other liabilities December 31, 2017 Fair value hedges $ 35,635 $ (999 ) Other liabilities
Gains (Losses) on Derivative Instruments	The table below identifies the gains and losses recognized on Heartland's derivative instruments designated as cash flow hedges for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Effective Portion Ineffective Portion Recognized in OCI Reclassified from AOCI into Income Recognized in Income on Derivatives Amount of Gain (Loss) Category Amount of Gain (Loss) Category Amount of Gain (Loss) Three Months Ended September 30, 2018 Interest rate swaps $ 375 Interest expense $ 21 Other income $ — Nine Months Ended September 30, 2018 Interest rate swaps $ 3,198 Interest expense $ (207 ) Other income $ — Three Months Ended September 30, 2017 Interest rate swaps $ 325 Interest expense $ (308 ) Other income $ — Nine Months Ended September 30, 2017 Interest rate swaps $ 349 Interest expense $ (1,005 ) Other income $ — The table below identifies the gains and losses recognized on Heartland's fair value hedges for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Amount of Gain (Loss) Income Statement Category Three Months Ended September 30, 2018 Fair value hedges $ 179 Interest income Nine Months Ended September 30, 2018 Fair value hedges $ 1,423 Interest income Three Months Ended September 30, 2017 Fair value hedges $ (63 ) Interest income Nine Months Ended September 30, 2017 Fair value hedges $ 89 Interest income
Balance Sheet Category and Fair Values of Embedded Derivatives	The table below identifies the notional amount, fair value and balance sheet category of Heartland's embedded derivatives at September 30, 2018 , and December 31, 2017 , in thousands: Notional Amount Fair Value Balance Sheet Category September 30, 2018 Embedded derivatives $ 13,643 $ 215 Other assets December 31, 2017 Embedded derivatives $ 14,045 $ 738 Other assets The table below identifies the gains and losses recognized on Heartland's embedded derivatives for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Amount of Gain (Loss) Income Statement Category Three Months Ended September 30, 2018 Embedded derivatives $ 108 Other noninterest income Nine Months Ended September 30, 2018 Embedded derivatives $ 523 Other noninterest income Three Months Ended September 30, 2017 Embedded derivatives $ (296 ) Other noninterest income Nine Months Ended September 30, 2017 Embedded derivatives $ (181 ) Other noninterest income
Schedule of Other Derivatives Not Designated as Hedging Instruments, Balance Sheet and Income Category	The table below identifies the balance sheet category and fair values of Heartland's other free standing derivative instruments not designated as hedging instruments at September 30, 2018 , and December 31, 2017 , in thousands: Balance Sheet Category Notional Amount Fair Value September 30, 2018 Interest rate lock commitments (mortgage) Other assets $ 52,649 $ 1,539 Forward commitments Other assets 82,500 353 Forward commitments Other liabilities 33,500 (69 ) Undesignated interest rate swaps Other liabilities 13,643 (215 ) December 31, 2017 Interest rate lock commitments (mortgage) Other assets $ 53,588 $ 1,738 Forward commitments Other assets 37,286 80 Forward commitments Other liabilities 118,632 (232 ) Undesignated interest rate swaps Other liabilities 14,045 (738 ) The table below identifies the income statement category of the gains and losses recognized in income on Heartland's other free standing derivative instruments not designated as hedging instruments for the three- and nine- month periods ended September 30, 2018 , and September 30, 2017 , in thousands: Income Statement Category Gain (Loss) Recognized Three Months Ended September 30, 2018 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (4,470 ) Forward commitments Net gains on sale of loans held for sale 644 Undesignated interest rate swaps Other noninterest income 108 Nine Months Ended September 30, 2018 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (1,849 ) Forward commitments Net gains on sale of loans held for sale 352 Undesignated interest rate swaps Other noninterest income 523 Three Months Ended September 30, 2017 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (1,245 ) Forward commitments Net gains on sale of loans held for sale 72 Undesignated interest rate swaps Other noninterest income 88 Nine Months Ended September 30, 2017 Interest rate lock commitments (mortgage) Net gains on sale of loans held for sale $ (587 ) Forward commitments Net gains on sale of loans held for sale (2,304 ) Undesignated interest rate swaps Other noninterest income 203

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The table below presents Heartland's assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2018 , and December 31, 2017 , in thousands, aggregated by the level in the fair value hierarchy within which those measurements fall: Total Fair Value Level 1 Level 2 Level 3 September 30, 2018 Assets Securities available for sale U.S. government corporations and agencies $ 26,997 $ 25,367 $ 1,630 $ — Mortgage and asset-backed securities 1,871,819 — 1,871,819 — Obligations of states and political subdivisions 358,483 — 358,483 — Equity securities with a readily determinable fair value 16,916 — 16,916 — Derivative financial instruments (1) 9,327 — 9,327 — Interest rate lock commitments 1,539 — — 1,539 Forward commitments 353 — 353 — Total assets at fair value $ 2,285,434 $ 25,367 $ 2,258,528 $ 1,539 Liabilities Derivative financial instruments (2) $ 5,940 $ — $ 5,940 $ — Forward commitments 69 — 69 — Total liabilities at fair value $ 6,009 $ — $ 6,009 $ — December 31, 2017 Assets Securities available for sale U.S. government corporations and agencies $ 5,328 $ 3,484 $ 1,844 $ — Mortgage and asset-backed securities 1,753,736 — 1,753,736 — Obligations of states and political subdivisions 441,015 — 441,015 — Equity securities 16,674 — 16,674 — Derivative financial instruments (1) 3,933 — 3,933 — Interest rate lock commitments 1,738 — — 1,738 Forward commitments 80 — 80 — Total assets at fair value $ 2,222,504 $ 3,484 $ 2,217,282 $ 1,738 Liabilities Derivative financial instruments (2) $ 5,167 $ — $ 5,167 $ — Forward commitments 232 — 232 — Total liabilities at fair value $ 5,399 $ — $ 5,399 $ — (1) Includes cash flow hedges, embedded derivatives and back-to-back loan swaps (2) Includes cash flow hedges, fair value hedges, back-to-back loan swaps, embedded conversion options and free standing derivative instruments
Fair Value Measurements, Nonrecurring	The tables below present Heartland's assets that are measured at fair value on a nonrecurring basis, in thousands: Fair Value Measurements at Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Year-to- Date (Gains) Losses Collateral dependent impaired loans: Commercial $ 6,772 $ — $ — $ 6,772 $ 237 Commercial real estate 420 — — 420 72 Agricultural and agricultural real estate 11,821 — — 11,821 495 Residential real estate 590 — — 590 — Consumer 1,942 — — 1,942 — Total collateral dependent impaired loans $ 21,545 $ — $ — $ 21,545 $ 804 Loans held for sale $ 77,727 $ — $ 77,727 $ — $ (835 ) Other real estate owned $ 11,908 $ — $ — $ 11,908 $ 1,847 Premises, furniture and equipment held for sale $ 4,422 $ — $ — $ 4,422 $ (74 ) Fair Value Measurements at December 31, 2017 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Year-to- Collateral dependent impaired loans: Commercial $ 3,212 $ — $ — $ 3,212 $ 1,119 Commercial real estate 9,480 — — 9,480 322 Agricultural and agricultural real estate 8,406 — — 8,406 2,028 Residential real estate 1,137 — — 1,137 — Consumer 1,234 — — 1,234 — Total collateral dependent impaired loans $ 23,469 $ — $ — $ 23,469 $ 3,469 Loans held for sale $ 44,560 $ — $ 44,560 $ — $ 190 Other real estate owned $ 10,777 $ — $ — $ 10,777 $ 737 Premises, furniture and equipment held for sale $ 1,977 $ — $ — $ 1,977 $ 192 Commercial servicing rights $ 291 $ — $ — $ 291 $ (21 )
Fair Value Inputs, Assets, Quantitative Information	The following tables present additional quantitative information about assets measured at fair value and for which Heartland has utilized Level 3 inputs to determine fair value, in thousands: Fair Value at 9/30/2018 Valuation Unobservable Range Interest rate lock commitments $ 1,539 Discounted cash flows Closing ratio 0-99% (1) Other real estate owned 11,908 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Premises, furniture and equipment held for sale 4,422 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Collateral dependent impaired loans: Commercial 6,772 Modified appraised value Third party appraisal (2) Appraisal discount 0-13% (3) Commercial real estate 420 Modified appraised value Third party appraisal (2) Appraisal discount 0-12% (3) Agricultural and agricultural real estate 11,821 Modified appraised value Third party appraisal (2) Appraisal discount 0-15% (3) Residential real estate 590 Modified appraised value Third party appraisal (2) Appraisal discount 0-24% (3) Consumer 1,942 Modified appraised value Third party valuation (2) Valuation discount 0-14% (3) (1) The significant unobservable input used in the fair value measurement is the closing ratio, which represents the percentage of loans currently in a lock position which management estimates will ultimately close. The closing ratio calculation takes into consideration historical data and loan-level data. The weighted average closing ratio for Heartland's legacy mortgage operations is 86%. The weighted average closing ratio for PrimeWest Mortgage Corporation is 95%. (2) Third party appraisals are obtained and updated at least annually to establish the value of the underlying asset, but the disclosure of the unobservable inputs used by the appraisers would not be meaningful because the range will vary widely from appraisal to appraisal. (3) Discounts applied to the appraised values primarily include estimated sales costs, but also consider the age of the appraisal, changes in local market conditions and changes in the current condition of the collateral. Fair Value at 12/31/2017 Valuation Technique Unobservable Input Range (Weighted Average) Interest rate lock commitments $ 1,738 Discounted cash flows Closing ratio 0-99% (89%) (1) Other real estate owned 10,777 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Commercial servicing rights 291 Discounted cash flows Third party valuation (3) Premises, furniture and equipment held for sale 1,977 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Other real estate owned 10,777 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Collateral dependent impaired loans: Commercial 3,212 Modified appraised value Third party appraisal (2) Appraisal discount 0-15% (3) Commercial real estate 9,480 Modified appraised value Third party appraisal (2) Appraisal discount 0-12% (3) Agricultural and agricultural real estate 8,406 Modified appraised value Third party appraisal (2) Appraisal discount 0-10% (3) Residential real estate 1,137 Modified appraised value Third party appraisal (2) Appraisal discount 0-12% (3) Consumer 1,234 Modified appraised value Third party valuation (2) Valuation discount 0-12% (3) (1) The significant unobservable input used in the fair value measurement is the closing ratio, which represents the percentage of loans currently in a lock position which management estimates will ultimately close. The closing ratio calculation takes into consideration historical data and loan-level data. (2) Third party appraisals are obtained and updated at least annually to establish the value of the underlying asset, but the disclosure of the unobservable inputs used by the appraisers would not be meaningful because the range will vary widely from appraisal to appraisal. (3) Discounts applied to the appraised values primarily include estimated sales costs, but also consider the age of the appraisal, changes in local market conditions and changes in the current condition of the collateral.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The changes in fair value of the interest rate lock commitments, which are Level 3 financial instruments measured on a recurring basis, are summarized in the following table, in thousands: For the Nine Months Ended For the Year Ended December 31, 2017 Balance at January 1, $ 1,738 $ 2,790 Acquired interest rate lock commitments 1,383 — Total gains (losses) included in earnings (1,849 ) (1,479 ) Issuances 1,661 1,875 Settlements (1,394 ) (1,448 ) Balance at period end $ 1,539 $ 1,738
Fair Value, by Balance Sheet Grouping	Heartland does not believe that the estimated information presented herein is representative of the earnings power or value of Heartland. The following analysis, which is inherently limited in depicting fair value, also does not consider any value associated with either existing customer relationships or the ability of Heartland to create value through loan origination, deposit gathering or fee generating activities. Many of the estimates presented herein are based upon the use of highly subjective information and assumptions and, accordingly, the results may not be precise. Management believes that fair value estimates may not be comparable between financial institutions due to the wide range of permitted valuation techniques and numerous estimates which must be made. Furthermore, because the disclosed fair value amounts were estimated as of the balance sheet date, the amounts actually realized or paid upon maturity or settlement of the various financial instruments could be significantly different. Fair Value Measurements at Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 437,375 $ 437,375 $ 437,375 $ — $ — Time deposits in other financial institutions 5,836 5,836 5,836 — — Securities: Carried at fair value 2,274,215 2,274,215 25,367 2,248,848 — Held to maturity 239,908 247,394 — 247,394 — Other investments 26,656 26,656 — 26,656 — Loans held for sale 77,727 77,727 — 77,727 — Loans, net: Commercial 1,939,469 1,906,941 — 1,900,169 6,772 Commercial real estate 3,623,768 3,611,265 — 3,610,845 420 Agricultural and agricultural real estate 570,320 563,262 — 551,441 11,821 Residential real estate 673,628 663,234 — 662,644 590 Consumer 497,151 494,379 — 492,437 1,942 Total Loans, net 7,304,336 7,239,081 — 7,217,536 21,545 Cash surrender value on life insurance 162,216 162,216 — 162,216 — Derivative financial instruments (1) 9,126 9,126 — 9,126 — Interest rate lock commitments 1,539 1,539 — — 1,539 Forward commitments 353 353 — 353 — Financial liabilities: Deposits Demand deposits 3,427,819 3,427,819 — 3,427,819 — Savings deposits 4,958,430 4,958,430 — 4,958,430 — Time deposits 1,125,914 1,125,914 — 1,125,914 — Short term borrowings 131,139 131,139 — 131,139 — Other borrowings 277,563 279,087 — 279,087 — Derivative financial instruments (2) 5,739 5,940 — 5,940 — Forward commitments 69 69 — 69 — (1) Includes cash flow hedges, embedded derivatives and back-to-back loan swaps (2) Includes cash flow hedges, fair value hedges, back-to-back loan swaps, embedded conversion options and free standing derivative instruments Fair Value Measurements at December 31, 2017 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 196,003 $ 196,003 $ 196,003 $ — $ — Time deposits in other financial institutions 9,820 9,820 9,820 — — Securities: Carried at fair value 2,216,753 2,216,753 3,484 2,213,269 — Held to maturity 253,550 265,494 — 265,494 — Other investments 22,563 22,563 — 22,563 — Loans held for sale 44,560 44,560 — 44,560 — Loans, net: Commercial 1,628,043 1,617,956 — 1,614,744 3,212 Commercial real estate 3,140,427 3,132,542 — 3,123,062 9,480 Agricultural and agricultural real estate 508,075 508,987 — 500,581 8,406 Residential real estate 620,939 614,667 — 613,530 1,137 Consumer 438,294 440,820 — 439,586 1,234 Total Loans, net 6,335,778 6,314,972 — 6,291,503 23,469 Cash surrender value on life insurance 142,818 142,818 — 142,818 — Derivative financial instruments (1) 3,933 3,933 — 3,933 — Interest rate lock commitments 1,738 1,738 — — 1,738 Forward commitments 80 80 — 80 — Financial liabilities: Deposits Demand deposits 2,983,128 2,983,128 — 2,983,128 — Savings deposits 4,240,328 4,240,328 — 4,240,328 — Time deposits 923,453 923,453 — 923,453 — Short term borrowings 324,691 324,691 — 324,691 — Other borrowings 285,011 285,609 — 285,609 — Derivative financial instruments (2) 5,167 5,167 — 5,167 — Forward commitments 232 232 — 232 — (1) Includes cash flow hedges, embedded derivatives and back-to-back loan swaps (2) Includes cash flow hedges, fair value hedges, back-to-back loan swaps, embedded conversion options and free standing derivative instruments

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Schedule of noninterest income in-scope and out-of-scope of Topic 606	The following presents noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the three- and nine-months ended September 30, 2018, and 2017, in thousands: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 In-scope of Topic 606 Service charges and fees Service charges and fees on deposit accounts $ 2,858 $ 2,577 $ 8,270 $ 7,002 Overdraft fees 2,990 2,479 7,716 6,950 Customer service fees 101 102 266 217 Credit card fee income 3,062 1,994 8,443 6,212 Debit card income 3,883 2,985 10,349 8,908 Other service charges 1 1 2 2 Total service charges and fees $ 12,895 $ 10,138 $ 35,046 $ 29,291 Trust fees 4,499 3,872 13,794 11,482 Brokerage and insurance commissions 1,111 950 2,895 2,962 Total noninterest income in-scope of Topic 606 $ 18,505 $ 14,960 $ 51,735 $ 43,735 Out-of-scope of Topic 606 Loan servicing income $ 1,670 $ 1,161 $ 5,231 $ 4,236 Securities gains/(losses), net (145 ) 1,679 1,037 5,553 Unrealized gain on equity securities, net 54 — 97 — Net gains on sale of loans held for sale 7,410 4,997 18,261 17,961 Valuation adjustment on commercial servicing rights 230 5 12 29 Income on bank owned life insurance 892 766 2,206 2,039 Other noninterest income 1,149 1,409 3,536 2,941 Total noninterest income out-of-scope of Topic 606 11,260 10,017 30,380 32,759 Total noninterest income $ 29,765 $ 24,977 $ 82,115 $ 76,494

Basis of Presentation (Narrativ

Basis of Presentation (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of business segments	2

Basis of Presentation (Earnings

Basis of Presentation (Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share
Net income	$ 33,710	$ 21,632	$ 84,857	$ 61,600
Preferred dividends	(13)	(13)	(39)	(45)
Interest expense on convertible preferred debt	0	3	0	12
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 33,697	$ 21,622	$ 84,818	$ 61,567
Weighted average common shares outstanding for basic earnings per share (in shares)	34,452	29,648	32,520	27,569
Assumed incremental common shares issued upon non-vested restricted stock units (in shares)	192	262	187	265
Weighted average common shares for diluted earnings per share (in shares)	34,644	29,910	32,707	27,834
Earnings per common share — basic (in dollars per share)	$ 0.98	$ 0.73	$ 2.61	$ 2.23
Earnings per common share — diluted (in dollars per share)	$ 0.97	$ 0.72	$ 2.59	$ 2.21
Number of antidilutive common stock equivalents excluded from diluted earnings per share computation (in shares)	0	0	0	0

Basis of Presentation (Stock-Ba

Basis of Presentation (Stock-Based Compensation) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit from equity based awards			$ 672,000	$ 1,100,000
Options granted (in shares)			0	0
Intrinsic value for the total of all options exercised			$ 231,000
Cash received from options exercised			$ 121,000	$ 254,000
Options vested during period (in shares)			0	0
2017 and 2018 RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, period before change in control			6 months
Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Typical options expiration period after date of grant			10 years
Time-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	3 years
Performance-Based RSUs | Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	1 year		1 year
Performance-Based RSUs | Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	3 years		3 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation costs			$ 3,700,000	$ 3,600,000
Share-based unrecognized compensation costs			5,300,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation costs			0	$ 0
Share-based unrecognized compensation costs			$ 0
Stock Options | Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods			5 years
Stock Options | Period One | Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods			3 years
Stock Options | Period Two | Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods			4 years
Stock Options | Period Three | Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods			5 years
Long-Term Incentive Plan 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares for issuance under future awards (in shares)			442,320
Long-Term Incentive Plan 2012 | Time-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	52,153	55,665
Long-Term Incentive Plan 2012 | Performance-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, vesting percentage after change in control			100.00%
Long-Term Incentive Plan 2012 | Performance-Based RSUs | 2017 and 2018 RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, vesting percentage after change in control			100.00%
Share-based compensation, vesting period after change in control			24 months
Long-Term Incentive Plan 2012 | Performance-Based RSUs | Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	18,988	27,570
Long-Term Incentive Plan 2012 | Performance-Based RSUs | Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	16,108	9,032
Long-Term Incentive Plan 2012 | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)			29,048	16,804

Basis of Presentation (Summary

Basis of Presentation (Summary of RSUs Outstanding) (Details) - RSUs - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Shares
Outstanding at beginning of period (in shares)	301,578	346,817
Granted (in shares)	116,297	109,071
Vested (in shares)	(127,429)	(136,428)
Forfeited (in shares)	(27,678)	(12,923)
Outstanding at end of period (in shares)	262,768	306,537
Weighted-Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)	$ 34.74	$ 27.61
Granted (in dollars per share)	55.26	47.21
Vested (in dollars per share)	32.70	26.66
Forfeited (in dollars per share)	45.58	31.57
Outstanding at end of period (in dollars per share)	$ 43.65	$ 34.72

Basis of Presentation (Summar_2

Basis of Presentation (Summary of Stock Options Outstanding) (Details) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Shares
Outstanding at beginning of period (in shares)	6,500	26,400
Granted (in shares)	0	0
Exercised (in shares)	(6,500)	(13,650)
Forfeited (in shares)	0	(500)
Outstanding at end of period (in shares)	0	12,250
Options exercisable at end of period (in shares)	0	12,250
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 18.60	$ 18.60
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	18.60	18.60
Forfeited (in dollars per share)	0	18.60
Outstanding at end of period (in dollars per share)	0	18.60
Options exercisable at end of period (in dollars per share)	$ 0	$ 18.60

Basis of Presentation (Effect o

Basis of Presentation (Effect of New Financial Accounting Standards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of unrealized net gain on equity securities	$ 0
AOCI Attributable to Parent
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of unrealized net gain on equity securities	(280)
AOCI Attributable to Parent | ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of unrealized net gain on equity securities		$ (280)
AOCI Attributable to Parent | ASU 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment	(4,500)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of unrealized net gain on equity securities	280
Retained Earnings | ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of unrealized net gain on equity securities		$ 280
Retained Earnings | ASU 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment	$ 4,500

Acquisitions (Narrative) (Detai

Acquisitions (Narrative) (Details) $ in Thousands	May 18, 2018USD ($)shares	Feb. 23, 2018USD ($)shares	Jul. 07, 2017USD ($)buildingshares	Feb. 28, 2017USD ($)buildingshares	Jun. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Held to maturity						$ 7,365,493	$ 6,391,464
Deposits acquired						9,512,163	8,146,909
Goodwill resulting from acquisition						391,668	236,615
Balance of nonaccrual loans						73,060	62,581
Assets acquired						11,335,132	$ 9,810,739
First Bank Lubbock Bancshares, Inc.
Business Acquisition [Line Items]
Total consideration transferred in acquisition	$ 189,905
Purchase price in cash	$ 5,451
Purchase price paid by delivery of shares of common stock (in shares) | shares	3,350,664
Outstanding debt extinguished	$ 3,900
Trust preferred securities assumed	12,077
Total assets acquired	1,120,000
Goodwill resulting from acquisition	121,400
Transaction costs	6,000
Pre-tax merger related costs						1,100
Balance of nonaccrual loans						$ 7,600
Signature Bancshares, Inc.
Business Acquisition [Line Items]
Total consideration transferred in acquisition		$ 61,400
Purchase price in cash		$ 7,800
Purchase price paid by delivery of shares of common stock (in shares) | shares		1,000,843
Goodwill resulting from acquisition		$ 33,700
Citywide Banks
Business Acquisition [Line Items]
Total consideration transferred in acquisition			$ 211,200
Purchase price in cash			$ 58,600
Purchase price paid by delivery of shares of common stock (in shares) | shares			3,216,161
Held to maturity			$ 985,400
Deposits acquired			1,210,000
Goodwill resulting from acquisition			95,200
Assets acquired			$ 1,490,000
Number of bank buildings sold (building) | building			1
Fair value of buildings sold			$ 1,400
Founders Bancorp
Business Acquisition [Line Items]
Total consideration transferred in acquisition				$ 31,000
Purchase price in cash				$ 8,400
Purchase price paid by delivery of shares of common stock (in shares) | shares				455,877
Deposits acquired				$ 181,500
Goodwill resulting from acquisition				13,800
Assets acquired				$ 213,900
Number of bank buildings sold (building) | building				1
Fair value of buildings sold					$ 576
Loans acquired				$ 96,400
First Bank Lubbock Bancshares, Inc.
Business Acquisition [Line Items]
Held to maturity	681,100
Deposits acquired	893,800
Signature Bancshares, Inc.
Business Acquisition [Line Items]
Outstanding debt extinguished		5,900
Held to maturity		324,500
Deposits acquired		357,300
Assets acquired		$ 427,100
Stock Appreciation Rights (SARs) | First Bank Lubbock Bancshares, Inc.
Business Acquisition [Line Items]
Payment to holders of FBLB's stock appreciation rights	13,300
Trust Preferred Securities Subject to Mandatory Redemption | First Bank Lubbock Bancshares, Inc.
Business Acquisition [Line Items]
Trust preferred securities assumed	$ 8,200

Acquisitions (Acquisitions fair

Acquisitions (Acquisitions fair values) (Details) - USD ($) $ in Thousands	May 18, 2018	Sep. 30, 2018	Dec. 31, 2017
Fair value of liabilities assumed
Goodwill resulting from acquisition		$ 391,668	$ 236,615
First Bank Lubbock Bancshares, Inc.
Fair value of consideration paid:
Common stock	$ 184,454
Common stock (in shares)	3,350,664
Cash	$ 5,451
Total consideration paid	189,905
Fair value of assets acquired
Cash and due from banks	212,105
Securities:
Carried at fair value	1,788
Other securities	3,268
Loans held for sale	31,050
Loans held to maturity	681,080
Premises, furniture and equipment, net	23,271
Other real estate, net	379
Mortgage servicing rights	6,995
Core deposit intangibles and customer relationships, net	13,908
Cash surrender value on life insurance	14,997
Other assets	7,185
Total assets	996,026
Fair value of liabilities assumed
Deposits	893,827
Other borrowings	12,077
Other liabilities	21,580
Total liabilities assumed	927,484
Fair value of net assets acquired	68,542
Goodwill resulting from acquisition	$ 121,400

Acquisitions (Pro forma informa

Acquisitions (Pro forma information) (Details) - First Bank Lubbock Bancshares, Inc. - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Net interest income	$ 317,846	$ 262,367
Net income available to common stockholders	$ 69,075	$ 76,698
Basic earnings per share (in dollars per share)	$ 2.02	$ 2.48
Diluted earnings per share (in dollars per share)	$ 2.01	$ 2.46

Securities (Securities availabl

Securities (Securities available for sale) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,342,977	$ 2,248,181
Equity securities with a readily determinable fair value	16,916
Total	2,342,977
Gross Unrealized Gains	1,580
Gross Unrealized Losses	(70,342)
Estimated Fair Value	2,274,215	2,216,753
Estimated Fair Value	2,274,215
Amortized Cost		2,248,181
Gross Unrealized Gains		10,911
Gross Unrealized Losses		(42,339)
Securities available for sale		2,216,753
Total debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,326,061
Gross Unrealized Gains	1,580
Gross Unrealized Losses	(70,342)
Estimated Fair Value	2,257,299
Amortized Cost		2,231,885
Gross Unrealized Gains		10,533
Gross Unrealized Losses		(42,339)
Securities available for sale		2,200,079
U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,112
Gross Unrealized Gains	0
Gross Unrealized Losses	(115)
Estimated Fair Value	26,997
Amortized Cost		5,358
Gross Unrealized Gains		8
Gross Unrealized Losses		(38)
Securities available for sale		5,328
Mortgage and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,926,803
Gross Unrealized Gains	1,341
Gross Unrealized Losses	(56,325)
Estimated Fair Value	1,871,819
Amortized Cost		1,785,467
Gross Unrealized Gains		5,856
Gross Unrealized Losses		(37,587)
Securities available for sale		1,753,736
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	372,146
Gross Unrealized Gains	239
Gross Unrealized Losses	(13,902)
Estimated Fair Value	$ 358,483
Amortized Cost		441,060
Gross Unrealized Gains		4,669
Gross Unrealized Losses		(4,714)
Securities available for sale		441,015
Equity securities with a readily determinable fair value
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		16,296
Gross Unrealized Gains		378
Gross Unrealized Losses		0
Securities available for sale		$ 16,674

Securities (Narrative) (Details

Securities (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Investment [Line Items]
Reclassification of unrealized gain in fair value on equity securities						$ 0
Equity securities with a readily determinable fair value	$ 16,916,000		$ 16,916,000
Equity securities, at fair value	16,916,000		16,916,000
Unrealized net gains on equity securities recognized in current earnings	54,000	$ 0	97,000	$ 0
Fair value of securities pledged	551,300,000		551,300,000			670,300,000
Gross realized gains on available-for-sale securities			0	$ 0
Equity securities without readily determinable fair value	22,400,000		22,400,000			18,600,000
Shares of stock in FHLB	$ 15,100,000		$ 15,100,000			14,000,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Investment [Line Items]
Percentage of mortgage and asset-backed securities issued by government-sponsored enterprises	70.00%		70.00%
Retained Earnings
Investment [Line Items]
Reclassification of unrealized gain in fair value on equity securities						$ 280,000
Retained Earnings | ASU 2016-01
Investment [Line Items]
Reclassification of unrealized gain in fair value on equity securities					$ 280,000

Securities (Held to maturity se

Securities (Held to maturity securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 239,908	$ 253,550
Gross Unrealized Gains	8,422	12,460
Gross Unrealized Losses	(936)	(516)
Estimated Fair Value	247,394	265,494
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	239,908	253,550
Gross Unrealized Gains	8,422	12,460
Gross Unrealized Losses	(936)	(516)
Estimated Fair Value	$ 247,394	$ 265,494

Securities (Securities availa_2

Securities (Securities available for sale debt maturities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost
Due in 1 year or less	$ 23,216
Due in 1 to 5 years	50,520
Due in 5 to 10 years	131,431
Due after 10 years	194,091
Total debt securities	399,258
Mortgage and asset-backed securities	1,926,803
Equity securities with a readily determinable fair value	16,916
Amortized Cost	2,342,977	$ 2,248,181
Estimated Fair Value
Due in 1 year or less	23,161
Due in 1 to 5 years	49,592
Due in 5 to 10 years	125,824
Due after 10 years	186,903
Total debt securities	385,480
Mortgage and asset-backed securities	1,871,819
Equity securities with a readily determinable fair value	16,916
Estimated Fair Value	$ 2,274,215	$ 2,216,753

Securities (Securities held to

Securities (Securities held to maturity debt maturities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost
Due in 1 year or less	$ 1,274
Due in 1 to 5 years	31,121
Due in 5 to 10 years	105,183
Due after 10 years	102,330
Amortized Cost	239,908	$ 253,550
Estimated Fair Value
Due in 1 year or less	1,281
Due in 1 to 5 years	31,495
Due in 5 to 10 years	107,052
Due after 10 years	107,566
Estimated Fair Value	$ 247,394	$ 265,494

Securities (Gross realized gain

Securities (Gross realized gain (loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 59,137	$ 503,083	$ 694,872	$ 1,127,091
Gross security gains	67	2,088	3,537	8,585
Gross security losses	$ 212	$ 409	$ 2,500	$ 3,023

Securities (Debt securities ava

Securities (Debt securities available for sale) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value
Less than 12 months	$ 1,232,833
12 months or longer	812,622
Total	2,045,455
Less than 12 months		$ 948,929
12 months or longer		559,158
Total		1,508,087
Unrealized Losses
Less than 12 months	(23,890)
12 months or longer	(46,452)
Total	(70,342)
Less than 12 months		(12,238)
12 months or longer		(30,101)
Total		(42,339)
U.S. government corporations and agencies
Fair Value
Less than 12 months	22,392
12 months or longer	4,605
Total	26,997
Less than 12 months		4,819
12 months or longer		0
Total		4,819
Unrealized Losses
Less than 12 months	(39)
12 months or longer	(76)
Total	(115)
Less than 12 months		(38)
12 months or longer		0
Total		(38)
Mortgage and asset-backed securities
Fair Value
Less than 12 months	1,007,078
12 months or longer	668,623
Total	1,675,701
Less than 12 months		851,070
12 months or longer		399,978
Total		1,251,048
Unrealized Losses
Less than 12 months	(18,299)
12 months or longer	(38,026)
Total	(56,325)
Less than 12 months		(11,533)
12 months or longer		(26,054)
Total		(37,587)
Obligations of states and political subdivisions
Fair Value
Less than 12 months	203,363
12 months or longer	139,394
Total	342,757
Less than 12 months		93,040
12 months or longer		159,180
Total		252,220
Unrealized Losses
Less than 12 months	(5,552)
12 months or longer	(8,350)
Total	$ (13,902)
Less than 12 months		(667)
12 months or longer		(4,047)
Total		$ (4,714)

Securities (Securities held t_2

Securities (Securities held to maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value
Less than 12 months	$ 29,174	$ 8,512
12 months or longer	13,160	8,989
Total	42,334	17,501
Unrealized Losses
Less than 12 months	(209)	(49)
12 months or longer	(727)	(467)
Total	(936)	(516)
Obligations of states and political subdivisions
Fair Value
Less than 12 months	29,174	8,512
12 months or longer	13,160	8,989
Total	42,334	17,501
Unrealized Losses
Less than 12 months	(209)	(49)
12 months or longer	(727)	(467)
Total	$ (936)	$ (516)

Loans (Loans receivable) (Detai

Loans (Loans receivable) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Loans and Leases [Line Items]
Gross loans receivable held to maturity	$ 7,368,123	$ 6,393,226
Unearned discount	(1,340)	(556)
Deferred loan fees	(1,290)	(1,206)
Total net loans receivable held to maturity	7,365,493	6,391,464
Allowance for loan losses	(61,221)	(55,686)
Loans receivable, net	7,304,272	6,335,778
Commercial
Loans and Leases [Line Items]
Gross loans receivable held to maturity	5,610,953	4,809,875
Commercial | Commercial
Loans and Leases [Line Items]
Gross loans receivable held to maturity	1,962,222	1,646,606
Commercial | Commercial real estate
Loans and Leases [Line Items]
Gross loans receivable held to maturity	3,648,731	3,163,269
Agricultural and agricultural real estate
Loans and Leases [Line Items]
Gross loans receivable held to maturity	574,048	511,588
Residential real estate
Loans and Leases [Line Items]
Gross loans receivable held to maturity	676,941	624,279
Consumer
Loans and Leases [Line Items]
Gross loans receivable held to maturity	$ 506,181	$ 447,484
Consumer | Loans and Finance Receivables | Citizens Finance Co
Loans and Leases [Line Items]
Concentration risk, percentage	14.00%

Loans (Allowance for credit los

Loans (Allowance for credit losses on financing receivables) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance Under ASC 310-10-35	$ 6,003		$ 4,755
Ending Balance Under ASC 450-20	55,218		50,931
Total	61,221	$ 61,324	55,686	$ 54,885	$ 54,051	$ 54,324
Ending Balance Evaluated for Impairment Under ASC 310-10-35	87,669		78,468
Ending Balance Evaluated for Impairment Under ASC 450-20	7,280,454		6,314,758
Total	7,368,123		6,393,226
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	5,610,953		4,809,875
Commercial | Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance Under ASC 310-10-35	4,165		1,613
Ending Balance Under ASC 450-20	17,904		16,485
Total	22,069	20,709	18,098	16,970	17,168	14,765
Ending Balance Evaluated for Impairment Under ASC 310-10-35	23,414		7,415
Ending Balance Evaluated for Impairment Under ASC 450-20	1,938,808		1,639,191
Total	1,962,222		1,646,606
Commercial | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance Under ASC 310-10-35	214		766
Ending Balance Under ASC 450-20	23,476		21,184
Total	23,690	23,727	21,950	20,540	21,861	24,319
Ending Balance Evaluated for Impairment Under ASC 310-10-35	14,415		23,705
Ending Balance Evaluated for Impairment Under ASC 450-20	3,634,316		3,139,564
Total	3,648,731		3,163,269
Agricultural and agricultural real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance Under ASC 310-10-35	260		546
Ending Balance Under ASC 450-20	4,306		3,712
Total	4,566	5,709	4,258	6,127	3,832	4,210
Ending Balance Evaluated for Impairment Under ASC 310-10-35	17,522		13,304
Ending Balance Evaluated for Impairment Under ASC 450-20	556,526		498,284
Total	574,048		511,588
Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance Under ASC 310-10-35	279		430
Ending Balance Under ASC 450-20	1,571		1,794
Total	1,850	1,857	2,224	2,266	2,263	2,263
Ending Balance Evaluated for Impairment Under ASC 310-10-35	23,647		27,141
Ending Balance Evaluated for Impairment Under ASC 450-20	653,294		597,138
Total	676,941		624,279
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance Under ASC 310-10-35	1,085		1,400
Ending Balance Under ASC 450-20	7,961		7,756
Total	9,046	$ 9,322	9,156	$ 8,982	$ 8,927	$ 8,767
Ending Balance Evaluated for Impairment Under ASC 310-10-35	8,671		6,903
Ending Balance Evaluated for Impairment Under ASC 450-20	497,510		440,581
Total	$ 506,181		$ 447,484

Loans (Financing receivables, n

Loans (Financing receivables, non accrual status) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Nonaccrual loans	$ 68,528	$ 58,272
Nonaccrual troubled debt restructured loans	4,532	4,309
Total nonaccrual loans	73,060	62,581
Accruing loans past due 90 days or more	154	830
Performing troubled debt restructured loans	$ 4,180	$ 6,617

Loans (Troubled debt restructur

Loans (Troubled debt restructuring) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)loan	Sep. 30, 2017USD ($)loan	Sep. 30, 2018USD ($)loan	Sep. 30, 2017USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	8	11	25
Pre- Modification Recorded Investment	$ 92	$ 1,174	$ 2,098	$ 3,108
Post- Modification Recorded Investment	$ 94	$ 1,174	$ 1,808	$ 3,108
With Payment Defaults During the
Number of Loans | loan	4	5	10	8
Recorded Investment	$ 418	$ 1,221	$ 1,598	$ 1,480
Commercial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	0	3
Pre- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 131
Post- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 131
With Payment Defaults During the
Number of Loans | loan	0	0	0	0
Recorded Investment	$ 0	$ 0	$ 0	$ 0
Commercial | Commercial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	0	3
Pre- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 131
Post- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 131
With Payment Defaults During the
Number of Loans | loan	0	0	0	0
Recorded Investment	$ 0	$ 0	$ 0	$ 0
Commercial | Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	0	0
Pre- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
With Payment Defaults During the
Number of Loans | loan	0	0	0	0
Recorded Investment	$ 0	$ 0	$ 0	$ 0
Agricultural and agricultural real estate
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	0	0
Pre- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
With Payment Defaults During the
Number of Loans | loan	0	0	0	0
Recorded Investment	$ 0	$ 0	$ 0	$ 0
Residential real estate
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	8	11	22
Pre- Modification Recorded Investment	$ 92	$ 1,174	$ 2,098	$ 2,977
Post- Modification Recorded Investment	$ 94	$ 1,174	$ 1,808	$ 2,977
With Payment Defaults During the
Number of Loans | loan	4	5	10	8
Recorded Investment	$ 418	$ 1,221	$ 1,598	$ 1,480
Consumer
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	0	0
Pre- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post- Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
With Payment Defaults During the
Number of Loans | loan	0	0	0	0
Recorded Investment	$ 0	$ 0	$ 0	$ 0

Loans (Troubled debt narrative)

Loans (Troubled debt narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)loan
Financing Receivable, Recorded Investment [Line Items]
Principal deferment collected from government guarantees	$ 356
Capitalized interest and escrow	$ 66
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Number of loan relationships | loan	0

Loans (Loans by credit quality

Loans (Loans by credit quality indicator) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	$ 7,368,123	$ 6,393,226
Loans delinquent 30 to 89 days, percentage	0.62%	0.27%
Loans secured by residential real estate property in process of foreclosure	$ 3,100
Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	6,905,159	$ 6,009,382
Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	$ 462,964	$ 383,844
Percent of nonaccrual loans	16.00%	16.00%
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Percent of loans	53.00%	52.00%
Substandard
Financing Receivable, Recorded Investment [Line Items]
Percent of loans	47.00%	48.00%
Commercial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	$ 5,610,953	$ 4,809,875
Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	5,293,214	4,538,284
Commercial | Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	317,739	271,591
Commercial | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	1,962,222	1,646,606
Commercial | Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	1,825,692	1,552,783
Commercial | Commercial | Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	136,530	93,823
Commercial | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	3,648,731	3,163,269
Commercial | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	3,467,522	2,985,501
Commercial | Commercial real estate | Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	181,209	177,768
Agricultural and agricultural real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	574,048	511,588
Agricultural and agricultural real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	476,261	451,539
Agricultural and agricultural real estate | Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	97,787	60,049
Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	676,941	624,279
Residential real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	644,592	586,623
Residential real estate | Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	32,349	37,656
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	506,181	447,484
Consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	491,092	432,936
Consumer | Nonpass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans receivable held to maturity	$ 15,089	$ 14,548

Loans (Past due financing recei

Loans (Past due financing receivables) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	$ 45,593	$ 18,137
Accruing Loans and Leases, Current	7,249,470	6,312,508
Nonaccrual	73,060	62,581
Total	7,368,123	6,393,226
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	30,733	13,375
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	14,706	3,932
90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	154	830
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	34,729	8,700
Accruing Loans and Leases, Current	5,540,910	4,777,349
Nonaccrual	35,314	23,826
Total	5,610,953	4,809,875
Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	22,053	6,015
Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	12,557	2,585
Commercial | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	119	100
Commercial | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	14,140	1,605
Accruing Loans and Leases, Current	1,924,173	1,637,773
Nonaccrual	23,909	7,228
Total	1,962,222	1,646,606
Commercial | Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	10,558	1,246
Commercial | Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	3,521	259
Commercial | Commercial | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	61	100
Commercial | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	20,589	7,095
Accruing Loans and Leases, Current	3,616,737	3,139,576
Nonaccrual	11,405	16,598
Total	3,648,731	3,163,269
Commercial | Commercial real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	11,495	4,769
Commercial | Commercial real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	9,036	2,326
Commercial | Commercial real estate | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	58	0
Agricultural and agricultural real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	2,475	738
Accruing Loans and Leases, Current	554,055	497,546
Nonaccrual	17,518	13,304
Total	574,048	511,588
Agricultural and agricultural real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	1,294	604
Agricultural and agricultural real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	1,146	134
Agricultural and agricultural real estate | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	35	0
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	3,085	2,292
Accruing Loans and Leases, Current	659,662	601,120
Nonaccrual	14,194	20,867
Total	676,941	624,279
Residential real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	2,893	2,022
Residential real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	192	270
Residential real estate | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	0	0
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	5,304	6,407
Accruing Loans and Leases, Current	494,843	436,493
Nonaccrual	6,034	4,584
Total	506,181	447,484
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	4,493	4,734
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	811	943
Consumer | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans and Leases, Past Due	$ 0	$ 730

Loans (Impaired loans) (Details

Loans (Impaired loans) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Unpaid Contractual Balance
Total impaired loans with a related allowance	$ 13,456	$ 13,456	$ 19,958
Total impaired loans without a related allowance	78,191	78,191	64,121
Total impaired loans held to maturity	91,647	91,647	84,079
Loan Balance
Total impaired loans with a related allowance	13,456	13,456	18,101
Total impaired loans without a related allowance	74,213	74,213	60,367
Total impaired loans held to maturity	87,669	87,669	78,468
Related Allowance Recorded	6,003	6,003	4,755
Avg. Loan Balance
Total impaired loans with a related allowance	13,214	15,944	22,949
Total impaired loans without a related allowance	69,101	66,590	62,296
Total impaired loans held to maturity	82,315	82,534	85,245
Interest Income Recognized
Total impaired loans with a related allowance	35	113	129
Total impaired loans without a related allowance	406	880	1,029
Total impaired loans held to maturity	441	993	1,158
Commercial
Unpaid Contractual Balance
Total impaired loans with a related allowance	7,516	7,516	14,217
Total impaired loans without a related allowance	31,768	31,768	20,486
Total impaired loans held to maturity	39,284	39,284	34,703
Loan Balance
Total impaired loans with a related allowance	7,516	7,516	12,360
Total impaired loans without a related allowance	30,313	30,313	18,760
Total impaired loans held to maturity	37,829	37,829	31,120
Related Allowance Recorded	4,379	4,379	2,379
Avg. Loan Balance
Total impaired loans with a related allowance	6,062	9,228	15,086
Total impaired loans without a related allowance	24,963	22,154	22,734
Total impaired loans held to maturity	31,025	31,382	37,820
Interest Income Recognized
Total impaired loans with a related allowance	20	72	73
Total impaired loans without a related allowance	262	478	679
Total impaired loans held to maturity	282	550	752
Commercial | Commercial
Unpaid Contractual Balance
Total impaired loans with a related allowance	6,768	6,768	2,292
Total impaired loans without a related allowance	18,003	18,003	6,243
Total impaired loans held to maturity	24,771	24,771	8,535
Loan Balance
Total impaired loans with a related allowance	6,768	6,768	2,292
Total impaired loans without a related allowance	16,646	16,646	5,123
Total impaired loans held to maturity	23,414	23,414	7,415
Related Allowance Recorded	4,165	4,165	1,613
Avg. Loan Balance
Total impaired loans with a related allowance	5,173	3,593	3,607
Total impaired loans without a related allowance	13,113	9,307	2,586
Total impaired loans held to maturity	18,286	12,900	6,193
Interest Income Recognized
Total impaired loans with a related allowance	16	52	39
Total impaired loans without a related allowance	182	277	165
Total impaired loans held to maturity	198	329	204
Commercial | Commercial real estate
Unpaid Contractual Balance
Total impaired loans with a related allowance	748	748	11,925
Total impaired loans without a related allowance	13,765	13,765	14,243
Total impaired loans held to maturity	14,513	14,513	26,168
Loan Balance
Total impaired loans with a related allowance	748	748	10,068
Total impaired loans without a related allowance	13,667	13,667	13,637
Total impaired loans held to maturity	14,415	14,415	23,705
Related Allowance Recorded	214	214	766
Avg. Loan Balance
Total impaired loans with a related allowance	889	5,635	11,479
Total impaired loans without a related allowance	11,850	12,847	20,148
Total impaired loans held to maturity	12,739	18,482	31,627
Interest Income Recognized
Total impaired loans with a related allowance	4	20	34
Total impaired loans without a related allowance	80	201	514
Total impaired loans held to maturity	84	221	548
Agricultural and agricultural real estate
Unpaid Contractual Balance
Total impaired loans with a related allowance	2,043	2,043	1,539
Total impaired loans without a related allowance	18,002	18,002	13,793
Total impaired loans held to maturity	20,045	20,045	15,332
Loan Balance
Total impaired loans with a related allowance	2,043	2,043	1,539
Total impaired loans without a related allowance	15,479	15,479	11,765
Total impaired loans held to maturity	17,522	17,522	13,304
Related Allowance Recorded	260	260	546
Avg. Loan Balance
Total impaired loans with a related allowance	3,000	2,369	3,437
Total impaired loans without a related allowance	15,837	14,726	9,654
Total impaired loans held to maturity	18,837	17,095	13,091
Interest Income Recognized
Total impaired loans with a related allowance	2	2	0
Total impaired loans without a related allowance	1	4	0
Total impaired loans held to maturity	3	6	0
Residential real estate
Unpaid Contractual Balance
Total impaired loans with a related allowance	869	869	1,568
Total impaired loans without a related allowance	22,778	22,778	25,573
Total impaired loans held to maturity	23,647	23,647	27,141
Loan Balance
Total impaired loans with a related allowance	869	869	1,568
Total impaired loans without a related allowance	22,778	22,778	25,573
Total impaired loans held to maturity	23,647	23,647	27,141
Related Allowance Recorded	279	279	430
Avg. Loan Balance
Total impaired loans with a related allowance	1,006	1,278	2,056
Total impaired loans without a related allowance	22,779	24,780	26,024
Total impaired loans held to maturity	23,785	26,058	28,080
Interest Income Recognized
Total impaired loans with a related allowance	4	10	15
Total impaired loans without a related allowance	121	320	277
Total impaired loans held to maturity	125	330	292
Consumer
Unpaid Contractual Balance
Total impaired loans with a related allowance	3,028	3,028	2,634
Total impaired loans without a related allowance	5,643	5,643	4,269
Total impaired loans held to maturity	8,671	8,671	6,903
Loan Balance
Total impaired loans with a related allowance	3,028	3,028	2,634
Total impaired loans without a related allowance	5,643	5,643	4,269
Total impaired loans held to maturity	8,671	8,671	6,903
Related Allowance Recorded	1,085	1,085	1,400
Avg. Loan Balance
Total impaired loans with a related allowance	3,146	3,069	2,370
Total impaired loans without a related allowance	5,522	4,930	3,884
Total impaired loans held to maturity	8,668	7,999	6,254
Interest Income Recognized
Total impaired loans with a related allowance	9	29	41
Total impaired loans without a related allowance	22	78	73
Total impaired loans held to maturity	$ 31	$ 107	$ 114

Loans (Carrying amount of loans

Loans (Carrying amount of loans acquired narrative) (Details) - USD ($) $ in Millions	May 18, 2018	Feb. 23, 2018
First Bank Lubbock Bancshares, Inc.
Business Acquisition [Line Items]
Estimated fair value of loans acquired	$ 696.9
Loans held to maturity	$ 681.1
Signature Bancshares, Inc.
Business Acquisition [Line Items]
Estimated fair value of loans acquired		$ 335.1
Loans held to maturity		324.5
Commercial | Signature Bancshares, Inc.
Business Acquisition [Line Items]
Loans held to maturity		$ 16

Loans (Carrying amount of loa_2

Loans (Carrying amount of loans acquired) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	$ 1,838,230	$ 1,470,025
Commercial | Commercial
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	309,339	188,327
Commercial | Commercial real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	1,202,839	1,055,041
Agricultural and agricultural real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	32,357	1,242
Residential real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	204,634	174,123
Consumer
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	89,061	51,292
Impaired Purchased Loans
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	9,600	3,738
Impaired Purchased Loans | Commercial | Commercial
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	9,078	952
Impaired Purchased Loans | Commercial | Commercial real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	302	2,572
Impaired Purchased Loans | Agricultural and agricultural real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	0	0
Impaired Purchased Loans | Residential real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	220	214
Impaired Purchased Loans | Consumer
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	0	0
Non Impaired Purchased Loans
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	1,828,630	1,466,287
Non Impaired Purchased Loans | Commercial | Commercial
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	300,261	187,375
Non Impaired Purchased Loans | Commercial | Commercial real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	1,202,537	1,052,469
Non Impaired Purchased Loans | Agricultural and agricultural real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	32,357	1,242
Non Impaired Purchased Loans | Residential real estate
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	204,414	173,909
Non Impaired Purchased Loans | Consumer
Loans covered by loss share agreement (carrying amount) [Line Items]
Purchased loans	$ 89,061	$ 51,292

Loans (Change in accretable yie

Loans (Change in accretable yield on acquired loans) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 463	$ 101	$ 57	$ 182
Original yield discount, net, at date of acquisition	0	0	508	0
Accretion	(93)	(700)	(943)	(1,074)
Reclassification from nonaccretable difference	186	654	934	947
Balance at end of period	$ 556	$ 55	$ 556	$ 55

Loans (Change in accretable y_2

Loans (Change in accretable yield on acquired loans narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan and lease losses	$ 61,221		$ 61,221		$ 55,686
Provision for loan losses	5,238	$ 5,705	14,332	$ 10,235
2015, 2016 and 2017 Acquisitions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractually required payments of loans acquired	36,900		36,900
Estimated fair value of loans acquired	21,800		21,800
Allowance for loan and lease losses	675		675		$ 139
Provision for loan losses			675	$ 5
2015 Acquisitions | Non Impaired Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractually required payments of loans acquired	3,670,000		3,670,000
Estimated fair value of loans acquired	$ 3,590,000		$ 3,590,000

Allowance for Loan Losses (Deta

Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	$ 61,324	$ 54,051	$ 55,686	$ 54,324
Charge-offs	(6,120)	(5,759)	(11,508)	(12,243)
Recoveries	779	888	2,711	2,569
Provision	5,238	5,705	14,332	10,235
Ending Balance	61,221	54,885	61,221	54,885
Agricultural and agricultural real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	5,709	3,832	4,258	4,210
Charge-offs	(1,145)	0	(1,357)	(888)
Recoveries	0	14	14	17
Provision	2	2,281	1,651	2,788
Ending Balance	4,566	6,127	4,566	6,127
Residential real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	1,857	2,263	2,224	2,263
Charge-offs	0	(142)	(211)	(541)
Recoveries	1	63	77	70
Provision	(8)	82	(240)	474
Ending Balance	1,850	2,266	1,850	2,266
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	9,322	8,927	9,156	8,767
Charge-offs	(1,831)	(1,750)	(4,462)	(4,982)
Recoveries	378	418	1,045	987
Provision	1,177	1,387	3,307	4,210
Ending Balance	9,046	8,982	9,046	8,982
Commercial | Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	20,709	17,168	18,098	14,765
Charge-offs	(2,945)	(1,954)	(4,717)	(3,310)
Recoveries	158	347	562	635
Provision	4,147	1,409	8,126	4,880
Ending Balance	22,069	16,970	22,069	16,970
Commercial real estate | Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	23,727	21,861	21,950	24,319
Charge-offs	(199)	(1,913)	(761)	(2,522)
Recoveries	242	46	1,013	860
Provision	(80)	546	1,488	(2,117)
Ending Balance	$ 23,690	$ 20,540	$ 23,690	$ 20,540

Goodwill, Core Deposit Premiu_3

Goodwill, Core Deposit Premium and Other Intangible Assets (Goodwill narrative) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2018	May 18, 2018	Feb. 23, 2018	Dec. 31, 2017	Jul. 07, 2017	Feb. 28, 2017
Goodwill [Line Items]
Goodwill		$ 391,668,000			$ 236,615,000
Goodwill impairment	$ 0
Core Deposits
Goodwill [Line Items]
Intangibles, amortization period		10 years
First Bank Lubbock Bancshares, Inc.
Goodwill [Line Items]
Goodwill			$ 121,400,000
First Bank Lubbock Bancshares, Inc. | Core Deposits
Goodwill [Line Items]
Intangibles recognized			$ 13,900,000
Signature Bancshares, Inc.
Goodwill [Line Items]
Goodwill				$ 33,700,000
Signature Bancshares, Inc. | Core Deposits
Goodwill [Line Items]
Intangibles recognized				$ 7,700,000
Citywide Banks
Goodwill [Line Items]
Goodwill						$ 95,200,000
Citywide Banks | Core Deposits
Goodwill [Line Items]
Intangibles recognized						$ 16,000,000
Founders Bancorp
Goodwill [Line Items]
Goodwill							$ 13,800,000
Founders Bancorp | Core Deposits
Goodwill [Line Items]
Intangibles recognized							$ 2,500,000

Goodwill, Core Deposit Premiu_4

Goodwill, Core Deposit Premium and Other Intangible Assets (Carrying amount of intangible assets (incl accumulated amortization) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 134,232	$ 112,043
Accumulated Amortization	52,122	50,983
Net Carrying Amount	82,110	61,060
Core deposit intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	83,639	62,008
Accumulated Amortization	33,820	27,086
Net Carrying Amount	49,819	34,922
Customer relationship intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,177	1,177
Accumulated Amortization	925	896
Net Carrying Amount	252	281
Mortgage servicing rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	42,616	42,139
Accumulated Amortization	12,445	18,891
Net Carrying Amount	30,171	23,248
Commercial servicing rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,800	6,719
Accumulated Amortization	4,932	4,110
Net Carrying Amount	$ 1,868	$ 2,609

Goodwill, Core Deposit Premiu_5

Goodwill, Core Deposit Premium and Other Intangible Assets (Estimated future amortization expense for amortizable intangible assets) (Details) $ in Thousands	Sep. 30, 2018USD ($)
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2018	$ 4,374
Year ending December 31,
2,019	17,107
2,020	14,759
2,021	12,496
2,022	10,014
2,023	8,178
Thereafter	15,182
Total	82,110
Core deposit intangibles
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2018	2,583
Year ending December 31,
2,019	9,452
2,020	8,230
2,021	7,036
2,022	5,634
2,023	4,933
Thereafter	11,951
Total	49,819
Customer relationship intangibles
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2018	10
Year ending December 31,
2,019	38
2,020	37
2,021	35
2,022	34
2,023	34
Thereafter	64
Total	252
Mortgage servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2018	1,642
Year ending December 31,
2,019	7,132
2,020	6,113
2,021	5,094
2,022	4,076
2,023	3,057
Thereafter	3,057
Total	30,171
Commercial servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2018	139
Year ending December 31,
2,019	485
2,020	379
2,021	331
2,022	270
2,023	154
Thereafter	110
Total	$ 1,868

Goodwill, Core Deposit Premiu_6

Goodwill, Core Deposit Premium and Other Intangible Assets (Mortgage and commercial loans servicing narrative) (Details)	May 18, 2018USD ($)subsidiary	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Valuation servicing rights in tranches [Line Items]
Mortgage loans serviced for others		$ 4,160,000,000		$ 4,160,000,000		$ 3,560,000,000
Custodial escrow balances maintained		43,200,000		43,200,000		17,300,000
Number of subsidiaries | subsidiary	2
Total net loans receivable held to maturity			$ 773,900,000
Amount derecognized						6,900,000
Loans serviced		32,039,000		32,039,000		25,857,000
Valuation allowance				0
Mortgage Servicing Rights
Valuation servicing rights in tranches [Line Items]
Servicing asset at amortized value		47,581,000	35,002,000	47,581,000	$ 35,002,000	37,100,000
Book value of loans		30,171,000	23,742,000	30,171,000	23,742,000	$ 23,248,000	$ 32,088,000
Amount derecognized				$ 0	6,940,000
Prepayment rate				8.46%		9.73%
Discount rate				9.19%		9.06%
Fees collected for servicing of mortgage loans		2,600,000	2,900,000	$ 7,300,000	9,300,000
Mortgage Servicing Rights 15-year Tranche
Valuation servicing rights in tranches [Line Items]
Servicing asset, agreement term	15 years
Mortgage Servicing Rights 30-year Tranche
Valuation servicing rights in tranches [Line Items]
Servicing asset, agreement term	30 years
Commercial Servicing Rights
Valuation servicing rights in tranches [Line Items]
Servicing asset at amortized value		2,529,000	3,458,000	2,529,000	3,458,000	$ 3,200,000
Book value of loans		1,868,000	2,857,000	1,868,000	2,857,000	2,609,000	$ 3,690,000
Loans serviced		114,500,000		$ 114,500,000		$ 139,900,000
Commercial Servicing Rights | Minimum
Valuation servicing rights in tranches [Line Items]
Prepayment rate				9.64%		7.27%
Discount rate				13.28%		13.04%
Commercial Servicing Rights | Maximum
Valuation servicing rights in tranches [Line Items]
Prepayment rate				11.94%		8.88%
Discount rate				16.55%		15.49%
Less Than 20 Years
Valuation servicing rights in tranches [Line Items]
Servicing asset at amortized value		607,000		$ 607,000		$ 740,000
Book value of loans		315,000		$ 315,000		537,000
Servicing asset, agreement term				20 years
Fees collected for servicing of mortgage loans		401,000	$ 394,000	$ 1,200,000	$ 1,200,000
Valuation allowance				$ 0		$ 0
Amortization period				20 years		20 years
More Than 20 Years
Valuation servicing rights in tranches [Line Items]
Servicing asset at amortized value		1,922,000		$ 1,922,000		$ 2,481,000
Book value of loans		$ 1,553,000		$ 1,553,000		2,084,000
Servicing asset, agreement term				20 years
Valuation allowance				$ 0		$ 12,000
Amortization period				20 years		20 years
First Bank Lubbock Bancshares, Inc. | Mortgage Servicing Rights
Valuation servicing rights in tranches [Line Items]
Servicing asset at amortized value	$ 7,000,000
Book value of loans	$ 640,700,000
Measurement Input, Cap Rate | Mortgage Servicing Rights | Minimum
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0089		0.0089		0.0094
Measurement Input, Cap Rate | Mortgage Servicing Rights | Maximum
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0125		0.0125		0.0150
Measurement Input, Cap Rate | Commercial Servicing Rights | Minimum
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0310		0.0310		0.0310
Measurement Input, Cap Rate | Commercial Servicing Rights | Maximum
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0445		0.0445		0.0445

Goodwill, Core Deposit Premiu_7

Goodwill, Core Deposit Premium and Other Intangible Assets (Changes in capitalized mortgage and commercial servicing rights) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Servicing Asset at Fair Value, Amount [Roll Forward]
Valuation allowance on commercial servicing rights	$ 230	$ 5	$ 12	$ 29
Sale of mortgage servicing rights					$ (6,900)
Mortgage Servicing Rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period			23,248	32,088	32,088
Originations			4,322	5,778
Amortization			(4,394)	(7,184)
Valuation allowance on commercial servicing rights			0	0
Sale of mortgage servicing rights			0	(6,940)
Acquired mortgage servicing rights			6,995	0
Balance at end of period	30,171	23,742	30,171	23,742	23,248
Fair value of commercial servicing rights	47,581	35,002	$ 47,581	$ 35,002	37,100
Commercial servicing rights, net to servicing portfolio			0.73%	0.67%
Commercial servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period			$ 2,609	$ 3,690	3,690
Originations			82	215
Amortization			(835)	(1,077)
Valuation allowance on commercial servicing rights			12	29
Balance at end of period	1,868	2,857	1,868	2,857	2,609
Fair value of commercial servicing rights	$ 2,529	$ 3,458	$ 2,529	$ 3,458	$ 3,200
Commercial servicing rights, net to servicing portfolio			1.63%	1.98%

Goodwill, Core Deposit Premiu_8

Goodwill, Core Deposit Premium and Other Intangible Assets (Book value, fair value of commercial serving rights and impairment) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Impairment	$ 0
15 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	4,056,000
Fair Value	6,488,000
Impairment	0
30 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	26,115,000
Fair Value	41,093,000
Impairment	0
Less Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	315,000	$ 537,000
Fair Value	607,000	740,000
Impairment	0	0
More Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	1,553,000	2,084,000
Fair Value	1,922,000	2,481,000
Impairment	0	12,000
Dubuque Bank and Trust Company | 15 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	2,371,000	2,858,000
Fair Value	4,747,000	4,988,000
Impairment	0	0
Dubuque Bank and Trust Company | 30 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	20,632,000	20,390,000
Fair Value	35,610,000	32,093,000
Impairment	0	0
First Bank & Trust | 15 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	1,685,000
Fair Value	1,741,000
Impairment	0
First Bank & Trust | 30 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	5,483,000
Fair Value	5,483,000
Impairment	0
Citywide Banks | Less Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	2,000	8,000
Fair Value	6,000	11,000
Impairment	0	0
Citywide Banks | More Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	30,000	34,000
Fair Value	33,000	37,000
Impairment	0	0
Premier Valley Bank | Less Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	53,000	83,000
Fair Value	82,000	110,000
Impairment	0	0
Premier Valley Bank | More Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	188,000	303,000
Fair Value	203,000	291,000
Impairment	0	12,000
Wisconsin Bank & Trust | 15 Years
Finite-Lived Intangible Assets [Line Items]
Book Value		2,858,000
Fair Value		4,988,000
Impairment		0
Wisconsin Bank & Trust | 30 Years
Finite-Lived Intangible Assets [Line Items]
Book Value		20,390,000
Fair Value		32,093,000
Impairment		0
Wisconsin Bank & Trust | Less Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	260,000	446,000
Fair Value	519,000	619,000
Impairment	0	0
Wisconsin Bank & Trust | More Than 20 Years
Finite-Lived Intangible Assets [Line Items]
Book Value	1,335,000	1,747,000
Fair Value	1,686,000	2,153,000
Impairment	$ 0	$ 0

Derivative Financial Instrume_3

Derivative Financial Instruments (Cash collateral on derivative financial instruments) (Narrative) (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Cash pledged as collateral	$ 0	$ 1,200,000
Counterparties
Derivative [Line Items]
Cash pledged as collateral	$ 2,000,000	$ 0

Derivative Financial Instrume_4

Derivative Financial Instruments (Cash flow hedges narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)transaction	May 18, 2018USD ($)
Derivative [Line Items]
Change in net unrealized losses on cash flow hedges	$ 207
Estimated amount to be reclassified from accumulated other comprehensive income to interest expense within the next twelve months	$ 83
Interest Rate Swap | Cash Flow Hedges
Derivative [Line Items]
Number of swap transactions | transaction	6
Derivative, notional amount	$ 105,000	$ 9,000
Interest Rate Swap | Cash Flow Hedges | Heartland Financial Statutory Trust IV, V and VII
Derivative [Line Items]
Derivative, notional amount	85,000
Interest Rate Swap | Cash Flow Hedges | Morrill Statutory Trust I and II
Derivative [Line Items]
Derivative, notional amount	$ 20,000
Interest Rate Swap | Cash Flow Hedges | OCGI Statutory Trust III
Derivative [Line Items]
Derivative, notional amount		3,000
Interest Rate Swap | Cash Flow Hedges | OCGI Capital Trust IV
Derivative [Line Items]
Derivative, notional amount		$ 6,000

Derivative Financial Instrume_5

Derivative Financial Instruments (Cash flow hedges balance sheet category and fair values) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other assets | Interest Rate Swap due March 17, 2021
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 25,000
Fair Value, Other Assets	$ 424
Receive Rate	2.334%
Weighted Average Pay Rate	2.255%
Other assets | Interest Rate Swap due March 26, 2019
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 10,000	$ 10,000
Fair Value, Other Assets	$ 42	$ 30
Receive Rate	2.374%	1.329%
Weighted Average Pay Rate	1.674%	1.674%
Other assets | Interest Rate Swap due March 18, 2019
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 10,000	$ 10,000
Fair Value, Other Assets	$ 42	$ 29
Receive Rate	2.334%	1.60%
Weighted Average Pay Rate	1.658%	1.658%
Other assets | Interest Rate Swap due May 10, 2021
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 30,667	$ 33,667
Fair Value, Other Assets	$ 1,089	$ 759
Receive Rate	4.633%	3.932%
Weighted Average Pay Rate	3.674%	3.674%
Other assets | Interest Rate Swap due June 15, 2024
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 20,000
Fair Value, Other Assets	$ 652
Receive Rate	2.334%
Weighted Average Pay Rate	2.39%
Other assets | Interest Rate Swap due March 1, 2024
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 20,000
Fair Value, Other Assets	$ 666
Receive Rate	2.321%
Weighted Average Pay Rate	2.352%
Other assets | Interest Rate Swap Due June 15, 2021
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 6,000
Fair Value, Other Assets	$ 175
Receive Rate	2.334%
Weighted Average Pay Rate	1.866%
Other assets | Interest Rate Swap Due June 30, 2021
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 3,000
Fair Value, Other Assets	$ 92
Receive Rate	2.436%
Weighted Average Pay Rate	1.878%
Other liabilities | Interest Rate Swap due March 17, 2021
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities		$ 25,000
Fair Value, Other Liabilities		$ (106)
Receive Rate		1.60%
Weighted Average Pay Rate		2.255%
Other liabilities | Interest Rate Swap due January 7, 2020
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities	$ 20,000	$ 20,000
Fair Value, Other Liabilities	$ (186)	$ (621)
Receive Rate	2.339%	1.35%
Weighted Average Pay Rate	3.355%	3.355%
Other liabilities | Interest Rate Swap Due July 24, 2028
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities	$ 29,500
Fair Value, Other Liabilities	$ (33)
Receive Rate	4.712%
Weighted Average Pay Rate	5.425%
Other liabilities | Interest Rate Swap due June 15, 2024
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities		$ 20,000
Fair Value, Other Liabilities		$ (177)
Receive Rate		1.588%
Weighted Average Pay Rate		2.39%
Other liabilities | Interest Rate Swap due March 1, 2024
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities		$ 20,000
Fair Value, Other Liabilities		$ (149)
Receive Rate		1.481%
Weighted Average Pay Rate		2.352%

Derivative Financial Instrume_6

Derivative Financial Instruments (Cash flow hedges gains (losses) recognized) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Trading Activity, Gains and Losses, Net [Line Items]
Effective Portion, Recognized in OCI, Amount of Gain (Loss)	$ 395	$ 17	$ 2,991	$ (656)
Interest rate swaps
Trading Activity, Gains and Losses, Net [Line Items]
Effective Portion, Recognized in OCI, Amount of Gain (Loss)	375	325	3,198	349
Interest rate swaps | Interest expense
Trading Activity, Gains and Losses, Net [Line Items]
Effective Portion, Reclassified from AOCI into Income, Amount of Gain (Loss)	21	(308)	(207)	(1,005)
Interest rate swaps | Other income
Trading Activity, Gains and Losses, Net [Line Items]
Ineffective Portion, Recognized in Income on Derivatives, Amount of Gain (Loss)	$ 0	$ 0	$ 0	$ 0

Derivative Financial Instrume_7

Derivative Financial Instruments (Fair value hedges narrative) (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Cash pledged as collateral	$ 0	$ 1,200,000
Fair Value Hedging | Interest Rate Swap
Derivative [Line Items]
Cash pledged as collateral	$ 3,200,000	$ 3,900,000

Derivative Financial Instrume_8

Derivative Financial Instruments (Fair value hedges balance sheet category and fair values) (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Feb. 05, 2016
Other liabilities
Derivative [Line Items]
Notional Amount			$ 2,000,000
Fair value hedges | Other assets
Derivative [Line Items]
Notional Amount	$ 30,954,000
Fair Value	625,000
Fair value hedges | Other liabilities
Derivative [Line Items]
Notional Amount	4,133,000	$ 35,635,000
Fair Value	$ (201,000)	$ (999,000)

Derivative Financial Instrume_9

Derivative Financial Instruments (Fair value hedges gans (losses) recognized) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair value hedges | Interest income
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss)	$ 179	$ (63)	$ 1,423	$ 89

Derivative Financial Instrum_10

Derivative Financial Instruments (Embedded derivatives blance sheet category and fair values) (Details) - Embedded derivatives - Other assets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 13,643	$ 14,045
Fair Value	$ 215	$ 738

Derivative Financial Instrum_11

Derivative Financial Instruments (Embedded derivatives gain (losses) recognized) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other noninterest income | Embedded derivatives
Derivative [Line Items]
Amount of Gain (Loss)	$ 108	$ (296)	$ 523	$ (181)

Derivative Financial Instrum_12

Derivative Financial Instruments (Embedded derivatives narrative) (Details)	Feb. 05, 2016USD ($)shares	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)shares	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)shares
Derivative [Line Items]
Number of shares to be issued upon conversion (in shares) | shares	73,394			0		0
Number of shares issued upon conversion (in shares) | shares						20,481
Embedded Conversion Option
Derivative [Line Items]
Derivative, notional amount		$ 0		$ 0		$ 0
Embedded Conversion Option | Other noninterest income
Derivative [Line Items]
Noninterest income recorded for embedded conversion option		$ 0	$ 285,000	$ 0	$ 422,000
Other liabilities
Derivative [Line Items]
Derivative, notional amount	$ 2,000,000

Derivative Financial Instrum_13

Derivative Financial Instruments (Back-to-back loan swaps narrative) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Cash pledged as collateral	$ 0		$ 1,200,000
Counterparties
Derivative [Line Items]
Cash pledged as collateral	2,000,000		0
Back-to-Back Loan Swaps | Interest Rate Swap
Derivative [Line Items]
Cash pledged as collateral	815,000		1,600,000
Back-to-Back Loan Swaps | Interest Rate Swap | Interest income
Derivative [Line Items]
Gain (loss) recognized	0	$ 0
Back-to-Back Loan Swaps | Interest Rate Swap | Counterparties
Derivative [Line Items]
Cash pledged as collateral	$ 2,500,000		$ 190,000

Derivative Financial Instrum_14

Derivative Financial Instruments (Back-to-back loan swaps balance sheet category and fair values) (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Feb. 05, 2016
Other liabilities
Derivative [Line Items]
Notional Amount			$ 2,000,000
Back-to-Back Loan Swaps | Other assets
Derivative [Line Items]
Notional Amount	$ 200,241,000	$ 126,766,000
Fair Value, Other Assets	5,305,000	2,377,000
Back-to-Back Loan Swaps | Other liabilities
Derivative [Line Items]
Notional Amount	200,241,000	126,766,000
Fair Value, Other Liabilities	$ (5,305,000)	$ (2,377,000)
Receive Rate | Back-to-Back Loan Swaps | Other assets
Derivative [Line Items]
Weighted Average Interest Rate (in percent)	5.07%	4.70%
Receive Rate | Back-to-Back Loan Swaps | Other liabilities
Derivative [Line Items]
Weighted Average Interest Rate (in percent)	4.68%	4.03%
Pay Rate | Back-to-Back Loan Swaps | Other assets
Derivative [Line Items]
Weighted Average Interest Rate (in percent)	4.68%	4.03%
Pay Rate | Back-to-Back Loan Swaps | Other liabilities
Derivative [Line Items]
Weighted Average Interest Rate (in percent)	5.07%	4.70%

Derivative Financial Instrum_15

Derivative Financial Instruments (Other free standing derivatives narrative) (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Cash pledged as collateral	$ 0	$ 1,200,000
Counterparties
Derivative [Line Items]
Cash pledged as collateral	2,000,000	0
Not Designated as Hedging Instrument
Derivative [Line Items]
Cash pledged as collateral	$ 35,000	20,000
Not Designated as Hedging Instrument | Counterparties
Derivative [Line Items]
Cash pledged as collateral		$ 29,000

Derivative Financial Instrum_16

Derivative Financial Instruments (Other free standing derivatives balance sheet category and fair values) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other assets | Interest rate lock commitments (mortgage)
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 52,649	$ 53,588
Fair Value, Other Assets	1,539	1,738
Other assets | Forward commitments
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	82,500	37,286
Fair Value, Other Assets	353	80
Other liabilities | Forward commitments
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities	33,500	118,632
Fair Value, Other Liabilities	(69)	(232)
Other liabilities | Undesignated interest rate swaps
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities	13,643	14,045
Fair Value, Other Liabilities	$ (215)	$ (738)

Derivative Financial Instrum_17

Derivative Financial Instruments (Other free standing derivatives gains (losses) recognized) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net gains on sale of loans held for sale | Interest rate lock commitments (mortgage)
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized	$ (4,470)	$ (1,245)	$ (1,849)	$ (587)
Net gains on sale of loans held for sale | Forward commitments
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized	644	72	352	(2,304)
Other noninterest income | Undesignated interest rate swaps
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized	$ 108	$ 88	$ 523	$ 203

Fair Value (Fair value measurem

Fair Value (Fair value measurement recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Securities available for sale	$ 2,274,215	$ 2,216,753
Equity securities with a readily determinable fair value	16,916
Securities available for sale		2,216,753
Level 1
Assets
Securities available for sale	25,367	3,484
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Level 2
Assets
Securities available for sale	2,248,848	2,213,269
Derivative assets	9,126	3,933
Liabilities
Derivative liabilities	5,940	5,167
Level 3
Assets
Securities available for sale	0	0
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Interest rate lock commitments | Level 1
Assets
Derivative assets	0	0
Interest rate lock commitments | Level 2
Assets
Derivative assets	0	0
Interest rate lock commitments | Level 3
Assets
Derivative assets	1,539	1,738
Forward commitments | Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Forward commitments | Level 2
Assets
Derivative assets	353	80
Liabilities
Derivative liabilities	69	232
Forward commitments | Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
U.S. government corporations and agencies
Assets
Securities available for sale	26,997
Securities available for sale		5,328
Mortgage and asset-backed securities
Assets
Securities available for sale	1,871,819
Securities available for sale		1,753,736
Obligations of states and political subdivisions
Assets
Securities available for sale	358,483
Securities available for sale		441,015
Equity securities with a readily determinable fair value
Assets
Securities available for sale		16,674
Recurring Basis
Assets
Equity securities with a readily determinable fair value	16,916
Total assets at fair value	2,285,434	2,222,504
Liabilities
Total liabilities at fair value	6,009	5,399
Recurring Basis | Level 1
Assets
Equity securities with a readily determinable fair value	0
Total assets at fair value	25,367	3,484
Liabilities
Total liabilities at fair value	0	0
Recurring Basis | Level 2
Assets
Equity securities with a readily determinable fair value	16,916
Total assets at fair value	2,258,528	2,217,282
Liabilities
Total liabilities at fair value	6,009	5,399
Recurring Basis | Level 3
Assets
Equity securities with a readily determinable fair value	0
Total assets at fair value	1,539	1,738
Liabilities
Total liabilities at fair value	0	0
Recurring Basis | Derivative Financial Instruments
Assets
Derivative assets	9,327	3,933
Liabilities
Derivative liabilities	5,940	5,167
Recurring Basis | Derivative Financial Instruments | Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis | Derivative Financial Instruments | Level 2
Assets
Derivative assets	9,327	3,933
Liabilities
Derivative liabilities	5,940	5,167
Recurring Basis | Derivative Financial Instruments | Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis | Interest rate lock commitments
Assets
Derivative assets	1,539	1,738
Recurring Basis | Interest rate lock commitments | Level 1
Assets
Derivative assets	0	0
Recurring Basis | Interest rate lock commitments | Level 2
Assets
Derivative assets	0	0
Recurring Basis | Interest rate lock commitments | Level 3
Assets
Derivative assets	1,539	1,738
Recurring Basis | Forward commitments
Assets
Derivative assets	353	80
Liabilities
Derivative liabilities	69	232
Recurring Basis | Forward commitments | Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis | Forward commitments | Level 2
Assets
Derivative assets	353	80
Liabilities
Derivative liabilities	69	232
Recurring Basis | Forward commitments | Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis | U.S. government corporations and agencies
Assets
Securities available for sale	26,997
Securities available for sale		5,328
Recurring Basis | U.S. government corporations and agencies | Level 1
Assets
Securities available for sale	25,367
Securities available for sale		3,484
Recurring Basis | U.S. government corporations and agencies | Level 2
Assets
Securities available for sale	1,630
Securities available for sale		1,844
Recurring Basis | U.S. government corporations and agencies | Level 3
Assets
Securities available for sale	0
Securities available for sale		0
Recurring Basis | Mortgage and asset-backed securities
Assets
Securities available for sale	1,871,819
Securities available for sale		1,753,736
Recurring Basis | Mortgage and asset-backed securities | Level 1
Assets
Securities available for sale	0
Securities available for sale		0
Recurring Basis | Mortgage and asset-backed securities | Level 2
Assets
Securities available for sale	1,871,819
Securities available for sale		1,753,736
Recurring Basis | Mortgage and asset-backed securities | Level 3
Assets
Securities available for sale	0
Securities available for sale		0
Recurring Basis | Obligations of states and political subdivisions
Assets
Securities available for sale	358,483
Securities available for sale		441,015
Recurring Basis | Obligations of states and political subdivisions | Level 1
Assets
Securities available for sale	0
Securities available for sale		0
Recurring Basis | Obligations of states and political subdivisions | Level 2
Assets
Securities available for sale	358,483
Securities available for sale		441,015
Recurring Basis | Obligations of states and political subdivisions | Level 3
Assets
Securities available for sale	$ 0
Securities available for sale		0
Recurring Basis | Equity securities with a readily determinable fair value
Assets
Securities available for sale		16,674
Recurring Basis | Equity securities with a readily determinable fair value | Level 1
Assets
Securities available for sale		0
Recurring Basis | Equity securities with a readily determinable fair value | Level 2
Assets
Securities available for sale		16,674
Recurring Basis | Equity securities with a readily determinable fair value | Level 3
Assets
Securities available for sale		$ 0

Fair Value (Fair value measur_2

Fair Value (Fair value measurement non-recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	$ 11,908	$ 10,777
Premises, furniture and equipment held for sale	4,422	1,977
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	77,727	44,560
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Other real estate owned	11,908	10,777
Commercial servicing rights | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights		291
Premises, furniture and equipment held for sale | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	4,422	1,977
Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	21,545	23,469
Loans held for sale	77,727	44,560
Other real estate owned	11,908	10,777
Nonrecurring Basis | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	804	3,469
Loans held for sale	(835)	190
Other real estate owned	1,847	737
Nonrecurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Loans held for sale	0	0
Other real estate owned	0	0
Nonrecurring Basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Loans held for sale	77,727	44,560
Other real estate owned	0	0
Nonrecurring Basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	21,545	23,469
Loans held for sale	0	0
Other real estate owned	11,908	10,777
Nonrecurring Basis | Commercial servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights		291
Nonrecurring Basis | Commercial servicing rights | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights		(21)
Nonrecurring Basis | Commercial servicing rights | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights		0
Nonrecurring Basis | Commercial servicing rights | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights		0
Nonrecurring Basis | Commercial servicing rights | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights		291
Nonrecurring Basis | Premises, furniture and equipment held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	4,422	1,977
Nonrecurring Basis | Premises, furniture and equipment held for sale | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	(74)	192
Nonrecurring Basis | Premises, furniture and equipment held for sale | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	0	0
Nonrecurring Basis | Premises, furniture and equipment held for sale | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	0	0
Nonrecurring Basis | Premises, furniture and equipment held for sale | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premises, furniture and equipment held for sale	4,422	1,977
Nonrecurring Basis | Commercial | Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	6,772	3,212
Nonrecurring Basis | Commercial | Commercial | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	237	1,119
Nonrecurring Basis | Commercial | Commercial | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Commercial | Commercial | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Commercial | Commercial | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	6,772	3,212
Nonrecurring Basis | Commercial | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	420	9,480
Nonrecurring Basis | Commercial | Commercial real estate | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	72	322
Nonrecurring Basis | Commercial | Commercial real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Commercial | Commercial real estate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Commercial | Commercial real estate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	420	9,480
Nonrecurring Basis | Agricultural and agricultural real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	11,821	8,406
Nonrecurring Basis | Agricultural and agricultural real estate | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	495	2,028
Nonrecurring Basis | Agricultural and agricultural real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Agricultural and agricultural real estate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Agricultural and agricultural real estate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	11,821	8,406
Nonrecurring Basis | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	590	1,137
Nonrecurring Basis | Residential real estate | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Residential real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Residential real estate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Residential real estate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	590	1,137
Nonrecurring Basis | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	1,942	1,234
Nonrecurring Basis | Consumer | Year-to- Date (Gains) Losses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Consumer | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Consumer | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	0	0
Nonrecurring Basis | Consumer | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	$ 1,942	$ 1,234

Fair Value (Quantitative Inform

Fair Value (Quantitative Information about Level 3 fair value measurements) (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other real estate owned	$ 11,908	$ 10,777
Premises, furniture and equipment held for sale	4,422	1,977
Securities available for sale	2,274,215	2,216,753
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0	0
Other real estate owned	11,908	10,777
Securities available for sale	0	0
Level 3 | Commercial servicing rights
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Commercial servicing rights		291
Level 3 | Premises, furniture and equipment held for sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Premises, furniture and equipment held for sale	4,422	1,977
Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1,539	1,738
Level 3 | Collateralized Debt Obligations [Member] | Commercial | Commercial
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities available for sale	6,772	3,212
Level 3 | Collateralized Debt Obligations [Member] | Commercial | Commercial real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities available for sale	420	9,480
Level 3 | Collateralized Debt Obligations [Member] | Agricultural and agricultural real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities available for sale	11,821	8,406
Level 3 | Collateralized Debt Obligations [Member] | Residential real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities available for sale	590	1,137
Level 3 | Collateralized Debt Obligations [Member] | Consumer
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities available for sale	$ 1,942	$ 1,234
Weighted Average | Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Closing ratio		0.89
Minimum | Commercial servicing rights
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	13.28%	13.04%
Maximum | Commercial servicing rights
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	16.55%	15.49%
Closing Ratio | Minimum | Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Closing ratio	0	0
Closing Ratio | Maximum | Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Closing ratio	0.99	0.99
Closing Ratio | Heartland Legacy Mortgage Operations | Weighted Average | Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Closing ratio	0.86
Closing Ratio | PrimeWest Mortgage Corporation | Weighted Average | Level 3 | Interest rate lock commitments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Closing ratio	0.95
Appraisal discount | Minimum | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Appraisal discount | Minimum | Level 3 | Commercial | Commercial
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Appraisal discount | Minimum | Level 3 | Commercial | Commercial real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Appraisal discount | Minimum | Level 3 | Agricultural and agricultural real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Appraisal discount | Minimum | Level 3 | Residential real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Appraisal discount | Minimum | Level 3 | Premises, furniture and equipment held for sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Appraisal discount | Maximum | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	10.00%	10.00%
Appraisal discount | Maximum | Level 3 | Commercial | Commercial
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	13.00%	15.00%
Appraisal discount | Maximum | Level 3 | Commercial | Commercial real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	12.00%	12.00%
Appraisal discount | Maximum | Level 3 | Agricultural and agricultural real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	15.00%	10.00%
Appraisal discount | Maximum | Level 3 | Residential real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	24.00%	12.00%
Appraisal discount | Maximum | Level 3 | Premises, furniture and equipment held for sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	10.00%	10.00%
Valuation discount | Minimum | Level 3 | Consumer
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	0.00%	0.00%
Valuation discount | Maximum | Level 3 | Consumer
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Pretax discount rate (percent)	14.00%	12.00%

Fair Value (Changes Level 3 ass

Fair Value (Changes Level 3 assets fair value, recurring) (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains included in net gains on sale of loans held for sale	$ 13,939	$ 11,968
Interest rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	1,738	$ 2,790	$ 2,790
Acquired interest rate lock commitments	1,383		0
Total gains (losses) included in earnings	(1,849)		(1,479)
Issuances	1,661		1,875
Settlements	(1,394)		(1,448)
Balance at period end	1,539		1,738
Gains included in net gains on sale of loans held for sale	$ 1,500		$ 1,700

Fair Value (Estimated fair valu

Fair Value (Estimated fair value financial instruments incl. carrying amounts) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Securities:
Securities available for sale	$ 2,274,215	$ 2,216,753
Held to maturity	247,394	265,494
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	437,375	196,003
Securities:
Securities available for sale	25,367	3,484
Held to maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans, net	0	0
Cash surrender value on life insurance	0	0
Derivative assets	0	0
Financial liabilities:
Short term borrowings	0	0
Other borrowings	0	0
Derivative liabilities	0	0
Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	0	0
Securities:
Securities available for sale	2,248,848	2,213,269
Held to maturity	247,394	265,494
Other investments	26,656	22,563
Loans held for sale	77,727	44,560
Loans, net	7,217,536	6,291,503
Cash surrender value on life insurance	162,216	142,818
Derivative assets	9,126	3,933
Financial liabilities:
Short term borrowings	131,139	324,691
Other borrowings	279,087	285,609
Derivative liabilities	5,940	5,167
Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and cash equivalents	0	0
Securities:
Securities available for sale	0	0
Held to maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans, net	21,545	23,469
Cash surrender value on life insurance	0	0
Derivative assets	0	0
Financial liabilities:
Short term borrowings	0	0
Other borrowings	0	0
Derivative liabilities	0	0
Carrying Amount
Financial assets:
Cash and cash equivalents	437,375	196,003
Securities:
Securities available for sale	2,274,215	2,216,753
Held to maturity	239,908	253,550
Other investments	26,656	22,563
Loans held for sale	77,727	44,560
Loans, net	7,304,336	6,335,778
Cash surrender value on life insurance	162,216	142,818
Derivative assets	9,126	3,933
Financial liabilities:
Short term borrowings	131,139	324,691
Other borrowings	277,563	285,011
Derivative liabilities	5,739	5,167
Estimated Fair Value
Financial assets:
Cash and cash equivalents	437,375	196,003
Securities:
Securities available for sale	2,274,215	2,216,753
Held to maturity	247,394	265,494
Other investments	26,656	22,563
Loans held for sale	77,727	44,560
Loans, net	7,239,081	6,314,972
Cash surrender value on life insurance	162,216	142,818
Derivative assets	9,126	3,933
Financial liabilities:
Short term borrowings	131,139	324,691
Other borrowings	279,087	285,609
Derivative liabilities	5,940	5,167
Interest rate lock commitments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Derivative assets	0	0
Interest rate lock commitments | Significant Other Observable Inputs (Level 2)
Securities:
Derivative assets	0	0
Interest rate lock commitments | Significant Unobservable Inputs (Level 3)
Securities:
Derivative assets	1,539	1,738
Interest rate lock commitments | Carrying Amount
Securities:
Derivative assets	1,539	1,738
Interest rate lock commitments | Estimated Fair Value
Securities:
Derivative assets	1,539	1,738
Forward commitments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Derivative assets	0	0
Financial liabilities:
Derivative liabilities	0	0
Forward commitments | Significant Other Observable Inputs (Level 2)
Securities:
Derivative assets	353	80
Financial liabilities:
Derivative liabilities	69	232
Forward commitments | Significant Unobservable Inputs (Level 3)
Securities:
Derivative assets	0	0
Financial liabilities:
Derivative liabilities	0	0
Forward commitments | Carrying Amount
Securities:
Derivative assets	353	80
Financial liabilities:
Derivative liabilities	69	232
Forward commitments | Estimated Fair Value
Securities:
Derivative assets	353	80
Financial liabilities:
Derivative liabilities	69	232
Commercial | Commercial | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Commercial | Commercial | Significant Other Observable Inputs (Level 2)
Securities:
Loans, net	1,900,169	1,614,744
Commercial | Commercial | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	6,772	3,212
Commercial | Commercial | Carrying Amount
Securities:
Loans, net	1,939,469	1,628,043
Commercial | Commercial | Estimated Fair Value
Securities:
Loans, net	1,906,941	1,617,956
Commercial | Commercial real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Commercial | Commercial real estate | Significant Other Observable Inputs (Level 2)
Securities:
Loans, net	3,610,845	3,123,062
Commercial | Commercial real estate | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	420	9,480
Commercial | Commercial real estate | Carrying Amount
Securities:
Loans, net	3,623,768	3,140,427
Commercial | Commercial real estate | Estimated Fair Value
Securities:
Loans, net	3,611,265	3,132,542
Agricultural and agricultural real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Agricultural and agricultural real estate | Significant Other Observable Inputs (Level 2)
Securities:
Loans, net	551,441	500,581
Agricultural and agricultural real estate | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	11,821	8,406
Agricultural and agricultural real estate | Carrying Amount
Securities:
Loans, net	570,320	508,075
Agricultural and agricultural real estate | Estimated Fair Value
Securities:
Loans, net	563,262	508,987
Residential real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Residential real estate | Significant Other Observable Inputs (Level 2)
Securities:
Loans, net	662,644	613,530
Residential real estate | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	590	1,137
Residential real estate | Carrying Amount
Securities:
Loans, net	673,628	620,939
Residential real estate | Estimated Fair Value
Securities:
Loans, net	663,234	614,667
Consumer | Quoted Prices in Active Markets for Identical Assets (Level 1)
Securities:
Loans, net	0	0
Consumer | Significant Other Observable Inputs (Level 2)
Securities:
Loans, net	492,437	439,586
Consumer | Significant Unobservable Inputs (Level 3)
Securities:
Loans, net	1,942	1,234
Consumer | Carrying Amount
Securities:
Loans, net	497,151	438,294
Consumer | Estimated Fair Value
Securities:
Loans, net	494,379	440,820
Time deposits in other financial institutions | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Time deposits in other financial institutions	5,836	9,820
Time deposits in other financial institutions | Significant Other Observable Inputs (Level 2)
Financial assets:
Time deposits in other financial institutions	0	0
Time deposits in other financial institutions | Significant Unobservable Inputs (Level 3)
Financial assets:
Time deposits in other financial institutions	0	0
Time deposits in other financial institutions | Carrying Amount
Financial assets:
Time deposits in other financial institutions	5,836	9,820
Time deposits in other financial institutions | Estimated Fair Value
Financial assets:
Time deposits in other financial institutions	5,836	9,820
Demand deposits | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial liabilities:
Deposits	0	0
Demand deposits | Significant Other Observable Inputs (Level 2)
Financial liabilities:
Deposits	3,427,819	2,983,128
Demand deposits | Significant Unobservable Inputs (Level 3)
Financial liabilities:
Deposits	0	0
Demand deposits | Carrying Amount
Financial liabilities:
Deposits	3,427,819	2,983,128
Demand deposits | Estimated Fair Value
Financial liabilities:
Deposits	3,427,819	2,983,128
Savings deposits | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial liabilities:
Deposits	0	0
Savings deposits | Significant Other Observable Inputs (Level 2)
Financial liabilities:
Deposits	4,958,430	4,240,328
Savings deposits | Significant Unobservable Inputs (Level 3)
Financial liabilities:
Deposits	0	0
Savings deposits | Carrying Amount
Financial liabilities:
Deposits	4,958,430	4,240,328
Savings deposits | Estimated Fair Value
Financial liabilities:
Deposits	4,958,430	4,240,328
Time deposits | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial liabilities:
Deposits	0	0
Time deposits | Significant Other Observable Inputs (Level 2)
Financial liabilities:
Deposits	1,125,914	923,453
Time deposits | Significant Unobservable Inputs (Level 3)
Financial liabilities:
Deposits	0	0
Time deposits | Carrying Amount
Financial liabilities:
Deposits	1,125,914	923,453
Time deposits | Estimated Fair Value
Financial liabilities:
Deposits	$ 1,125,914	$ 923,453

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Service charges and fees	$ 18,505	$ 14,960	$ 51,735	$ 43,735
Loan servicing income	1,670	1,161	5,231	4,236
Securities gains/(losses), net (includes $145 of net security losses and $1,679 of net security gains reclassified from accumulated other comprehensive income for the three months ended September 30, 2018 and 2017, respectively, and $1,037 and $5,553 of net security gains reclassified from accumulated other comprehensive income for the nine months ended September 30, 2018 and 2017, respectively)	(145)	1,679	1,037	5,553
Unrealized gain on equity securities, net	54	0	97	0
Net gains on sale of loans held for sale	7,410	4,997	18,261	17,961
Valuation adjustment on commercial servicing rights	230	5	12	29
Income on bank owned life insurance	892	766	2,206	2,039
Other noninterest income	1,149	1,409	3,536	2,941
Total noninterest income out-of-scope of Topic 606	11,260	10,017	30,380	32,759
TOTAL NONINTEREST INCOME	29,765	24,977	82,115	76,494
Service charges and fees on deposit accounts
Disaggregation of Revenue [Line Items]
Service charges and fees	2,858	2,577	8,270	7,002
Overdraft fees
Disaggregation of Revenue [Line Items]
Service charges and fees	2,990	2,479	7,716	6,950
Customer service fees
Disaggregation of Revenue [Line Items]
Service charges and fees	101	102	266	217
Credit card fee income
Disaggregation of Revenue [Line Items]
Service charges and fees	3,062	1,994	8,443	6,212
Debit card income
Disaggregation of Revenue [Line Items]
Service charges and fees	3,883	2,985	10,349	8,908
Other service charges
Disaggregation of Revenue [Line Items]
Service charges and fees	1	1	2	2
Total service charges and fees
Disaggregation of Revenue [Line Items]
Service charges and fees	12,895	10,138	35,046	29,291
Trust fees
Disaggregation of Revenue [Line Items]
Service charges and fees	4,499	3,872	13,794	11,482
Brokerage and insurance commissions
Disaggregation of Revenue [Line Items]
Service charges and fees	$ 1,111	$ 950	$ 2,895	$ 2,962