Business Combinations (Details) - USD ($) $ in Thousands		Feb. 01, 2021	Mar. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Cash and due from banks			$ 177,199	$ 150,464
Loans and leases, net	[1]		18,686,783	18,735,196
Premises and equipment, net			39,622	39,234
Goodwill			1,204,092	1,078,670
Finite Lived Core Deposits Customer Relations Net			21,312	23,641
Other assets			883,653	860,326
Assets			32,856,533	29,498,442
Noninterest-bearing deposits			11,017,462	9,193,827
Borrowings			19,750	5,000
Accrued interest payable and other liabilities			493,541	491,962
Liabilities			$ 29,202,396	$ 25,903,491
Civic
Business Acquisition [Line Items]
Cash and due from banks		$ 37,328
Loans and leases, net		65,600
Premises and equipment, net		1,194
Goodwill		125,422
Finite Lived Core Deposits Customer Relations Net		750
Other assets		77,725
Assets		308,019
Noninterest-bearing deposits		36,980
Borrowings		50,210
Accrued interest payable and other liabilities		61,592
Liabilities		148,782
Business Combination, Consideration Transferred		$ 159,237

[1] Excludes accrued interest receivable of $76.3 million and $79.7 million at March 31, 2021 and December 31, 2020, respectively, which is recorded in "Other assets" on the condensed consolidated balance sheets.