Mergers and Acquisitions - Pro Forma Combined Condensed Consolidated Financial Information (Details) - Brand Mortgage Group, LLC - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Net interest income - pro forma	$ 334,772	$ 341,946
Noninterest income - pro forma	115,798	117,476
Noninterest expense - pro forma	278,622	359,386
Net income - pro forma	$ 129,181	$ 72,719
Earnings per share - pro forma:
Basic (usd per share)	$ 2.21	$ 1.24
Diluted (usd per share)	$ 2.21	$ 1.24

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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