PARENT COMPANY ONLY FINANCIAL STATEMENTS - CONDENSED STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 08, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)		$ 34,136	$ (972)	$ 15,439
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of loan discounts, net		(4,755)	(8,358)	(4,806)
Amortization of issuance costs of subordinated notes		145	9	0
Provision for loan losses		14,360	64,700	17,864
Deferred income tax expense (benefit)		5,243	8,361	(3,409)
Increase in other assets, net		12,775	(16,520)	2,208
Increase in other liabilities, net		3,658	1,838	(1,379)
Net cash provided (used in) by operating activities		89,034	73,434	26,904
CASH FLOWS FROM INVESTING ACTIVITIES:
Net increase in loans held for investment and held for sale		(154,951)	(115,148)	(279,756)
Net cash (used by) provided by investing activities		(537,964)	(48,602)	(119,225)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of subordinated notes, net	$ 33,900	0	33,876	0
Common stock issued in connection with the exercise of stock options		486	3,046	1,534
Purchase of treasury stock		0	(1,253)	0
Net cash provided by financing activities		200,604	239,269	148,304
NET INCREASE IN CASH AND CASH EQUIVALENTS		(248,326)	264,101	55,983
CASH AND CASH EQUIVALENTS:
Beginning of year		389,007	124,906	68,923
End of year		140,681	389,007	124,906
Green Bancorp, Inc.
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)		34,136	(972)	15,439
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiary		(44,427)	(1,577)	(17,995)
Accretion of loan discounts, net		(7)	0	0
Amortization of debt valuation allowance		420	420	105
Amortization of issuance costs of subordinated notes		145	9	0
Provision for loan losses		10,536	0	0
Net loss on loans held-for-sale		138	0	0
Proceeds from sales of held-for-sale loans		12,560	0	0
Deferred income tax expense (benefit)		(1,074)	(130)	(18)
Increase in other assets, net		(6,148)	(41)	(295)
Increase in other liabilities, net		68	114	146
Net cash provided (used in) by operating activities		6,347	(2,177)	(2,618)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of loans from subsidiary		0	(32,819)	0
Capital contributed to subsidiary		(12,000)	0	0
Net increase in loans held for investment and held for sale		(4,886)	0	0
Net cash and cash equivalents paid in connection with acquisitions		0	0	2,740
Net cash (used by) provided by investing activities		(16,886)	(32,819)	2,740
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of subordinated notes, net		0	33,876	0
Common stock issued in connection with the exercise of stock options		486	3,046	1,534
Purchase of treasury stock		0	(1,253)	0
Net cash provided by financing activities		486	35,669	1,534
NET INCREASE IN CASH AND CASH EQUIVALENTS		(10,053)	673	1,656
CASH AND CASH EQUIVALENTS:
Beginning of year		10,995	10,322	8,666
End of year		$ 942	$ 10,995	$ 10,322