Business Combinations - Schedule of Supplemental Pro Forma Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		5 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings per share, Pro forma:
Net interest income, Pro forma	$ 130,967	$ 133,057
Provision for loan losses, Pro forma	976	2,287
Non-interest income, Pro forma	19,503	19,542
Non-interest expense, Pro forma	99,981	130,388
Provision (benefit) for income taxes, Pro Forma	9,317	4,354
Net income, Pro forma	$ 40,196	$ 15,570
Fully diluted, Pro forma (in usd per share)	$ 0.78	$ 0.30
Capital Bank
Earnings per share, Actual:
Net interest income, Actual			$ 8,043
Provision for loan losses, Actual			175
Non-interest income, Actual			557
Non-interest expense, Actual			9,180
Provision (benefit) for income taxes, Actual			(189)
Net Income, Actual			$ (566)
Sun Bancorp, Inc.
Earnings per share, Actual:
Net interest income, Actual				$ 31,056
Provision for loan losses, Actual				552
Non-interest income, Actual				3,747
Non-interest expense, Actual				19,270
Provision (benefit) for income taxes, Actual				3,146
Net Income, Actual				$ 11,835