Loans (Tables)

12 Months Ended

Dec. 31, 2017

Loans Receivable, Net [Abstract]

Schedule of Loans by Class

The following table presents loans by class as of the dates indicated:

December 31,	2017		2016
Real estate loans:
Commercial	$	2,822.9	$	1,834.4
Construction:
Land acquisition & development	348.7		208.5
Residential	240.2		147.9
Commercial	119.4		125.6
Total construction loans	708.3		482.0
Residential	1,487.4		1,027.4
Agricultural	158.2		170.2
Total real estate loans	5,176.8		3,514.0
Consumer:
Indirect consumer	784.7		752.4
Other consumer	175.1		148.1
Credit card	74.6		69.8
Total consumer loans	1,034.4		970.3
Commercial	1,215.4		797.9
Agricultural	136.2		132.9
Other, including overdrafts	4.9		1.6
Loans held for investment	7,567.7		5,416.7
Mortgage loans held for sale	46.6		61.8
Total loans	$	7,614.3	$	5,478.5

Deteriorated Loans Transferred in

The following table displays the outstanding unpaid principal balance and accrual status of loans acquired with credit impairment as of December 31, 2017 and 2016.    

December 31,	2017		2016
Outstanding principal	$	38.2	$	35.8
Carrying value:
Loans on accrual status	24.9		21.9
Total carrying value	$	24.9	$	21.9

The following table summarizes changes in the accretable yield for loans acquired credit impaired for the years ended December 31, 2017 and 2016:

Year Ended December 31,	2017			2016			2015
Beginning balance	$	6.8		$	6.7		$	5.8
Acquisitions	1.9			1.1			0.4
Accretion income	(2.9		)	(2.5		)	(2.9		)
Additions	0.1			—			0.6
Reductions due to exit events	(1.5		)	(1.1		)	(0.5		)
Reclassifications from nonaccretable differences	2.9			2.6			3.3
Ending balance	$	7.3		$	6.8		$	6.7

Schedule of Recorded Investment in Past Due Loans by Class

The following tables present the contractual aging of the Company’s recorded investment in past due loans by class as of the period indicated:

							Total Loans
	30 - 59		60 - 89		> 90		30 or More
	Days		Days		Days		Days		Current		Non-accrual		Total
As of December 31, 2017	Past Due		Past Due		Past Due		Past Due		Loans		Loans		Loans
Real estate
Commercial	$	2.9	$	0.5	$	0.3	$	3.7	$	2,792.4	$	26.8	$	2,822.9
Construction:
Land acquisition & development	7.3		0.3		0.3		7.9		337.8		3.0		348.7
Residential	2.1		—		—		2.1		236.4		1.7		240.2
Commercial	—		—		—		—		115.6		3.8		119.4
Total construction loans	9.4		0.3		0.3		10.0		689.8		8.5		708.3
Residential	13.3		1.4		0.4		15.1		1,464.1		8.2		1,487.4
Agricultural	0.3		—		0.2		0.5		154.3		3.4		158.2
Total real estate loans	25.9		2.2		1.2		29.3		5,100.6		46.9		5,176.8
Consumer:
Indirect consumer	7.8		2.1		0.4		10.3		772.6		1.8		784.7
Other consumer	1.6		0.5		0.1		2.2		172.6		0.3		175.1
Credit card	0.9		0.6		0.7		2.2		72.4		—		74.6
Total consumer loans	10.3		3.2		1.2		14.7		1,017.6		2.1		1,034.4
Commercial	3.9		1.7		0.7		6.3		1,189.5		19.6		1,215.4
Agricultural	1.8		0.1		—		1.9		133.5		0.8		136.2
Other, including overdrafts	—		—		—		—		4.9		—		4.9
Loans held for investment	41.9		7.2		3.1		52.2		7,446.1		69.4		7,567.7
Mortgage loans originated for sale	—		—		—		—		46.6		—		46.6
Total loans	$	41.9	$	7.2	$	3.1	$	52.2	$	7,492.7	$	69.4	$	7,614.3

							Total Loans
	30 - 59		60 - 89		> 90		30 or More
	Days		Days		Days		Days		Current		Non-accrual		Total
As of December 31, 2016	Past Due		Past Due		Past Due		Past Due		Loans		Loans		Loans
Real estate
Commercial	$	7.3	$	1.1	$	0.3	$	8.7	$	1,799.5	$	26.2	$	1,834.4
Construction:
Land acquisition & development	0.6		0.4		0.3		1.3		202.2		5.0		208.5
Residential	0.9		0.3		—		1.2		146.2		0.5		147.9
Commercial	—		—		—		—		124.8		0.8		125.6
Total construction loans	1.5		0.7		0.3		2.5		473.2		6.3		482.0
Residential	4.0		1.3		0.7		6.0		1,015.0		6.4		1,027.4
Agricultural	0.3		0.3		—		0.6		165.3		4.3		170.2
Total real estate loans	13.1		3.4		1.3		17.8		3,453.0		43.2		3,514.0
Consumer:
Indirect consumer	8.4		2.3		0.7		11.4		740.2		0.8		752.4
Other consumer	1.3		0.2		0.2		1.7		146.1		0.3		148.1
Credit card	0.5		0.3		0.6		1.4		68.4		—		69.8
Total consumer loans	10.2		2.8		1.5		14.5		954.7		1.1		970.3
Commercial	3.2		0.7		0.7		4.6		767.9		25.4		797.9
Agricultural	1.5		0.4		—		1.9		128.0		3.0		132.9
Other, including overdrafts	—		—		0.3		0.3		1.3		—		1.6
Loans held for investment	28.0		7.3		3.8		39.1		5,304.9		72.7		5,416.7
Mortgage loans originated for sale	—		—		—		—		61.8		—		61.8
Total loans	$	28.0	$	7.3	$	3.8	$	39.1	$	5,366.7	$	72.7	$	5,478.5

Schedule of Recorded Investment in Impaired Loans

The following tables present information on the Company’s recorded investment in impaired loans as of dates indicated:

	December 31, 2017
	Unpaid Total Principal Balance		Recorded Investment With No Allowance		Recorded Investment With Allowance		Total Recorded Investment		Related Allowance
Real estate:
Commercial	$	45.6	$	20.9	$	14.1	$	35.0	$	3.9
Construction:
Land acquisition & development	10.0		3.4		0.5		3.9		—
Residential	1.8		1.7		—		1.7		—
Commercial	4.7		0.4		3.5		3.9		2.2
Total construction loans	16.5		5.5		4.0		9.5		2.2
Residential	11.5		8.2		2.0		10.2		0.1
Agricultural	3.7		3.6		—		3.6		—
Total real estate loans	77.3		38.2		20.1		58.3		6.2
Commercial	29.5		12.4		11.4		23.8		4.4
Agricultural	1.1		0.8		0.3		1.1		0.2
Total	$	107.9	$	51.4	$	31.8	$	83.2	$	10.8

	December 31, 2016
	Unpaid Total Principal Balance		Recorded Investment With No Allowance		Recorded Investment With Allowance		Total Recorded Investment		Related Allowance
Real estate:
Commercial	$	57.0	$	24.4	$	21.4	$	45.8	$	2.8
Construction:
Land acquisition & development	12.1		4.3		1.8		6.1		0.8
Residential	1.6		0.2		0.6		0.8		—
Commercial	4.8		3.9		0.7		4.6		0.7
Total construction loans	18.5		8.4		3.1		11.5		1.5
Residential	8.2		4.1		2.5		6.6		0.3
Agricultural	5.1		4.5		0.2		4.7		—
Total real estate loans	88.8		41.4		27.2		68.6		4.6
Commercial	40.3		13.2		19.2		32.4		9.3
Agricultural	3.7		3.3		0.4		3.7		0.1
Total	$	132.8	$	57.9	$	46.8	$	104.7	$	14.0

	December 31, 2015
	Unpaid Total Principal Balance		Recorded Investment With No Allowance		Recorded Investment With Allowance		Total Recorded Investment		Related Allowance
Real estate:
Commercial	$	58.2	$	27.9	$	17.6	$	45.5	$	3.4
Construction:
Land acquisition & development	15.5		7.2		0.8		8.0		0.3
Residential	1.0		0.3		—		0.3		—
Commercial	1.3		0.3		0.7		1.0		0.7
Total construction loans	17.8		7.8		1.5		9.3		1.0
Residential	7.1		3.6		2.3		5.9		0.4
Agricultural	6.4		5.6		0.2		5.8		—
Total real estate loans	89.5		44.9		21.6		66.5		4.8
Commercial	29.6		10.8		13.7		24.5		6.5
Agricultural	1.3		0.6		0.4		1.0		0.3
Total	$	120.4	$	56.3	$	35.7	$	92.0	$	11.6

The following tables present the average recorded investment in and income recognized on impaired loans for the periods indicated:

	Year Ended December 31,
	2017				2016				2015
	Average Recorded Investment		Income Recognized		Average Recorded Investment		Income Recognized		Average Recorded Investment		Income Recognized
Real estate:
Commercial	$	40.4	$	0.3	$	46.9	$	0.2	$	39.2	$	0.8
Construction:
Land acquisition & development	5.0		—		8.0		0.1		8.3		0.1
Residential	1.3		—		0.8		—		0.3		—
Commercial	4.2		—		2.9		—		1.9		—
Total construction loans	10.5		—		11.7		0.1		10.5		0.1
Residential	8.4		—		6.2		—		4.1		—
Agricultural	4.2		—		4.4		—		7.2		—
Total real estate loans	63.5		0.3		69.2		0.3		61.0		0.9
Commercial	28.1		0.2		30.1		0.3		18.5		0.1
Agricultural	2.4		—		1.8		—		0.9		—
Total	$	94.0	$	0.5	$	101.1	$	0.6	$	80.4	$	1.0

Schedule of Loans Renegotiated in Troubled Debt Restructurings

The following table presents information on the Company's troubled debt restructurings that occurred during the periods indicated:

	Number of Notes	Type of Concession								Principal Balance at Restructure Date
Year Ended December 31, 2017		Interest only period		Extension of terms or maturity		Interest rate adjustment		Other
Real estate:
Commercial	5	$	1.5	$	0.4	$	—	$	0.9	$	2.8
Agriculture	1	—		0.8		—		—		0.8
Total real estate loans	6	1.5		1.2		—		0.9		3.6
Commercial	17	1.2		2.0		—		6.0		9.2
Agriculture	1	—		0.1		—		—		0.1
Total	24	$	2.7	$	3.3	$	—	$	6.9	$	12.9

	Number of Notes	Type of Concession								Principal Balance at Restructure Date
Year ended December 31, 2016		Interest only period		Extension of terms or maturity		Interest rate adjustment		Other
Real estate:
Commercial	18	$	0.4	$	5.5	$	0.2	$	1.8	$	7.9
Commercial construction	1	—		3.7		—		—		3.7
Residential	1	—		0.1		—		—		0.1
Total real estate loans	20	0.4		9.3		0.2		1.8		11.7
Commercial	13	4.4		0.4		—		3.3		8.1
Agriculture	2	—		0.3		—		—		0.3
Total	35	$	4.8	$	10.0	$	0.2	$	5.1	$	20.1

	Number of Notes	Type of Concession								Principal Balance at Restructure Date
Year ended December 31, 2015		Interest only period		Extension of terms or maturity		Interest rate adjustment		Other
Commercial real estate	2	$	—	$	0.6	$	—	$	0.1	$	0.7
Consumer	1	—		—		—		—		—
Commercial	12	—		8.7		3.3		0.5		12.5
Total	15	$	—	$	9.3	$	3.3	$	0.6	$	13.2

The following table presents information on the Company's troubled debt restructurings during the previous 12 months for which there was a payment default.

Year ended December 31, 2017	Number of Notes	Balance
Commercial	1	$	1.3
Total	1	$	1.3

Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator

The following tables present the Company’s recorded investment in criticized loans by class and credit quality indicator based on the most recent analysis performed as of the dates indicated:

As of December 31, 2017	Other Assets Especially Mentioned		Substandard		Doubtful		Total Criticized Loans
Real estate:
Commercial	$	78.0	$	96.4	$	10.3	$	184.7
Construction:
Land acquisition & development	3.2		16.4		—		19.6
Residential	2.3		1.7		0.5		4.5
Commercial	2.4		3.6		3.5		9.5
Total construction loans	7.9		21.7		4.0		33.6
Residential	3.9		12.5		1.9		18.3
Agricultural	4.3		19.1		—		23.4
Total real estate loans	94.1		149.7		16.2		260.0
Consumer:
Indirect consumer	0.8		2.2		0.3		3.3
Other consumer	0.4		0.7		0.2		1.3
Total consumer loans	1.2		2.9		0.5		4.6
Commercial	54.7		56.3		11.1		122.1
Agricultural	5.1		8.3		0.4		13.8
Total	$	155.1	$	217.2	$	28.2	$	400.5

As of December 31, 2016	Other Assets Especially Mentioned		Substandard		Doubtful		Total Criticized Loans
Real estate:
Commercial	$	85.3	$	85.3	$	10.8	$	181.4
Construction:
Land acquisition & development	13.4		6.2		1.4		21.0
Residential	0.4		1.6		0.7		2.7
Commercial	1.6		6.3		0.7		8.6
Total construction loans	15.4		14.1		2.8		32.3
Residential	5.0		12.5		0.8		18.3
Agricultural	3.8		17.8		—		21.6
Total real estate loans	109.5		129.7		14.4		253.6
Consumer:
Indirect consumer	0.8		1.5		0.1		2.4
Other consumer	0.7		1.0		0.3		2.0
Total consumer loans	1.5		2.5		0.4		4.4
Commercial	46.4		29.3		21.2		96.9
Agricultural	6.2		10.7		0.4		17.3
Total	$	163.6	$	172.2	$	36.4	$	372.2