Loan Servicing Rights (LSRs Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period	$ 63,841	$ 48,085	$ 0
Acquired in Talmer Bancorp, Inc. merger			42,462
Transfers in based on new accounting election		15,891
Additions from loans sold with servicing retained	8,226	8,745	1,030
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off	(2,881)	(2,505)	(519)
Changes in estimates of fair value	1,827	(6,375)	5,112
Fair value, end of period	71,013	63,841	48,085
Principal balance of loans serviced	6,868,079	7,108,747	5,300,171
Commercial Real Estate
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period	427	344	0
Acquired in Talmer Bancorp, Inc. merger			365
Transfers in based on new accounting election		0
Additions from loans sold with servicing retained	139	188	0
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off	(115)	(105)	(17)
Changes in estimates of fair value	0	0	(4)
Fair value, end of period	451	427	344
Principal balance of loans serviced	41,127	40,316	64,756
Mortgage
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period	63,414	47,741	0
Acquired in Talmer Bancorp, Inc. merger			42,097
Transfers in based on new accounting election		15,891
Additions from loans sold with servicing retained	8,087	8,557	1,030
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off	(2,766)	(2,400)	(502)
Changes in estimates of fair value	1,827	(6,375)	5,116
Fair value, end of period	70,562	63,414	47,741
Principal balance of loans serviced	$ 6,826,952	$ 7,068,431	$ 5,235,415

The value of the principal balance outstanding on loans sold to a third party and serviced by the company.

No definition available.

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- Definition

Servicing Asset At Fair Value, Additions From Merger

+ References

No definition available.

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- Definition

The value of new servicing assets from transfers, subsequently measured at fair value, acquired or created during the current period through purchases or from transfers of financial assets.

+ References

No definition available.

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- Definition

Servicing Asset At Fair Value, Adjustments For New Accounting Policy

+ References

No definition available.

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- Definition

The net increase (decrease) in fair value as a result of reductions from loans paid off used to calculate the fair value of servicing assets.

+ References

No definition available.

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in fair value from changes in the inputs, assumptions, or model used to calculate the fair value of the contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(4)(i)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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- References

No definition available.

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