Business Combinations and Asset Acquisitions	12 Months Ended
Business Combinations and Asset Acquisitions	Dec. 31, 2020
Business Combinations And Asset Acquisitions [Abstract]
Business Combinations and Asset Acquisitions	Business Combinations and Asset Acquisitions Bank Acquisitions On November 1, 2019, the Company completed its acquisition of SBC. SBC was the parent company of Countryside Bank. Through this business combination, the Company acquired Countryside Bank's six banking offices located in Countryside, Burbank, Darien, Homer Glen, Oak Brook and Chicago, Illinois. As of the acquisition date, the Company acquired approximately $619.8 million in assets, including approximately $423.0 million in loans, and approximately $507.8 million in deposits. The Company recorded goodwill of approximately $40.3 million related to the acquisition. On October 7, 2019, the Company completed its acquisition of STC. STC was the parent company of STC Capital Bank. Through this business combination, the Company acquired STC Capital Bank's five banking offices located in the communities of St. Charles, Geneva and South Elgin, Illinois. As of the acquisition date, the Company acquired approximately $250.1 million in assets, including approximately $174.3 million in loans, and approximately $201.2 million in deposits. The Company recorded goodwill of approximately $19.1 million related to the acquisition. On May 24, 2019, the Company completed its acquisition of ROC. ROC was the parent company of Oak Bank. Through this business combination, the Company acquired Oak Bank's one banking location in Chicago, Illinois. As of the acquisition date, the Company acquired approximately $223.4 million in assets, including approximately $124.7 million in loans, and approximately $161.2 million in deposits. The Company recorded goodwill of approximately $11.7 million related to the acquisition. On December 7, 2018, the Company completed its acquisition of certain assets and the assumption of certain liabilities of AEB. Through this asset acquisition, the Company acquired approximately $164.0 million in assets, including approximately $119.3 million in loans, and approximately $150.8 million in deposits. On August 1, 2018, the Company completed its acquisition of CSC. CSC was the parent company of Delaware Place Bank. Through this business combination, the Company acquired Delaware Place Bank's one banking location in Chicago, Illinois. As of the acquisition date, the Company acquired approximately $282.8 million in assets, including approximately $152.7 million in loans, and approximately $213.1 million in deposits. Additionally, the Company recorded goodwill of approximately $26.6 million related to the acquisition. Wealth Management Acquisitions On December 14, 2018, the Company acquired Elektra, the parent company of CDEC. CDEC is a provider of Qualified Intermediary services (as defined by U.S. Treasury regulations) for taxpayers seeking to structure tax-deferred like-kind exchanges under Internal Revenue Code Section 1031. CDEC has successfully facilitated more than 8,000 like-kind exchanges in the past decade for taxpayers nationwide. These transactions typically generate customer deposits during the period following the sale of the property until such proceeds are used to purchase a replacement property. The Company recorded goodwill of approximately $37.3 million related to the acquisition. Mortgage Banking Acquisitions On January 4, 2018, the Company acquired Veterans First with assets including mortgage-servicing-rights on approximately 10,000 loans, totaling an estimated $1.6 billion in unpaid principal balance. The Company recorded goodwill of approximately $9.1 million related to the acquisition.