CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($)	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comp. Income (Loss), net	BNC Bancorp Common Stock	BNC Bancorp Additional Paid-in Capital
Balance at Dec. 31, 2016	$ 1,496,695,000	$ 46,359,000	$ 1,083,491,000	$ 381,072,000	$ (14,227,000)
Balance (in shares) at Dec. 31, 2016		46,359,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of employee common stock options and related tax benefits	3,821,000	$ 194,000	3,627,000
Exercise of employee common stock options and related tax benefits (in shares)		194,000
Common dividends paid	(24,983,000)			(24,983,000)
Issuance of restricted common shares, net of forfeitures	0	$ 264,000	(264,000)
Issuance of restricted common shares, net of forfeitures (in shares)		264,000
Issuance of common equity, net of costs	192,194,000	$ 3,220,000	188,974,000
Stock Issued During Period, Value, Acquisitions	1,847,833,000					$ (27,687,000)	$ (1,820,146,000)
Issuance of common equity, net of costs (in shares)		3,220,000
Common stock issued in conjunction with acquisition (in shares)						27,687,000
Restricted shares withheld for taxes and related tax benefit	(4,880,000)	$ (72,000)	(4,808,000)
Stock-based compensation expense	14,412,000		14,412,000
Restricted shares withheld for taxes (in shares)		(72,000)
Net income	147,181,000			147,181,000
Other comprehensive income (loss)	1,076,000				1,076,000
Balance at Sep. 30, 2017	3,673,349,000	$ 77,652,000	3,105,578,000	503,270,000	(13,151,000)
Balance (in shares) at Sep. 30, 2017		77,652,000
Balance at Dec. 31, 2017	3,707,952,000	$ 77,740,000	3,115,304,000	519,144,000	(4,236,000)
Balance (in shares) at Dec. 31, 2017		77,740,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of employee common stock options and related tax benefits	1,700,000	$ 90,000	1,610,000
Exercise of employee common stock options and related tax benefits (in shares)		90,000
Common dividends paid	(32,903,000)			(32,903,000)
Issuance of restricted common shares, net of forfeitures	0	$ 141,000	(141,000)
Issuance of restricted common shares, net of forfeitures (in shares)		141,000
Restricted shares withheld for taxes and related tax benefit	(6,808,000)	$ (104,000)	(6,704,000)
Stock-based compensation expense	13,254,000		13,254,000
Restricted shares withheld for taxes (in shares)		(104,000)
Net income	264,122,000			264,122,000
Other comprehensive income (loss)	(50,276,000)				(50,276,000)
Balance at Sep. 30, 2018	$ 3,897,041,000	$ 77,867,000	$ 3,123,323,000	$ 750,363,000	$ (54,512,000)
Balance (in shares) at Sep. 30, 2018		77,867,000