Basis of Presentation (Details) $ in Thousands	Jun. 01, 2020 USD ($) office	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Total assets		$ 19,844,240	$ 11,776,012
Loans held for investment		13,450,840	8,722,311
Total deposits		$ 16,330,807	$ 8,898,509
Opus Bank
Business Acquisition [Line Items]
Total merger consideration	$ 749,605
Opus Bank | Opus Bank
Business Acquisition [Line Items]
Total assets	8,320,000
Loans held for investment	5,940,000
Total deposits	$ 6,910,000
Number of banking offices | office	46