Business Combinations - Summary of Purchase Price Calculation (Detail) $ / shares in Units, $ in Thousands	Apr. 01, 2019 USD ($) $ / shares shares	Mar. 31, 2020
Business Acquisition [Line Items]
Per share exchange ratio		0.3001
National Commerce Corporation [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding | shares	21,011,352
Per share exchange ratio	1.650
Number of shares of CenterState common stock less fractional shares | shares	34,667,968
CenterState common stock price per share | $ / shares	$ 23.81
Fair value of CenterState common stock issued	$ 825,444
Total cash consideration, not including cash for fractional shares	20
Total Cash Consideration	20
Total consideration paid to common shareholders	825,464
Fair value of stock options converted to CenterState stock options	5,848
Fair value of warrants converted to CenterState warrants	384
Total purchase price	$ 831,696