SHARE CAPITAL (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred shares issued	0	0
Preferred shares outstanding	0
Registration rights	50.00%
Aggregate principal amount of securities	$ 200,000,000
Stock Repurchase Program Expiration Date	Jun. 30, 2017
Common Class A
Class of Stock [Line Items]
Number of entitled votes per share	$ 1
Percentage of total voting power of all issued and outstanding ordinary shares	9.90%
Shares authorized to purchase under the share repurchase plan	2,000,000
Number of shares available under share repurchase plan	1,863,688
Increase (Decrease) in Common Stock [Roll Forward]
Balance – beginning of year	31,111,432	30,772,572	31,129,648
Issue of ordinary shares, net of forfeitures	129,530	338,860	256,464
Repurchase of ordinary shares	(136,312)	0	(613,540)
Class B shares converted to Class A shares	180	0	0
Balance – end of year	31,104,830	31,111,432	30,772,572
Par value per share	$ 0.10	$ 0.10
Common Class B
Class of Stock [Line Items]
Number of entitled votes per share	$ 10
Percentage of total voting power of all issued and outstanding ordinary shares	9.50%
Increase (Decrease) in Common Stock [Roll Forward]
Balance – beginning of year	6,254,895	6,254,895	6,254,895
Issue of ordinary shares, net of forfeitures	0	0	0
Repurchase of ordinary shares	0	0	0
Class B shares converted to Class A shares	(180)	0	0
Balance – end of year	6,254,715	6,254,895	6,254,895
Par value per share	$ 0.10	$ 0.10
Service Provider | Common Class A
Class of Stock [Line Items]
Shares authorized for issuance in relation to share purchase options granted to service provider	300,000	300,000
Shares available for future issuance	0	0
Stock Compensation Plan | Common Class A
Class of Stock [Line Items]
Shares authorized for the company's stock incentive plan	5,000,000	3,500,000
Shares available for future issuance	1,271,154	424,787
Greenlight Re
Increase (Decrease) in Common Stock [Roll Forward]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 33,000,000	$ 0	$ 5,000,000
Greenlight Re | Cayman Islands
Increase (Decrease) in Common Stock [Roll Forward]
Minimum net worth requirement	329,730,000	276,000,000
Insurance Regulations Minimum Capital Requirement	50,000,000
Statutory capital and surplus	762,200,000
Net income (loss)	(38,200,000)	44,800,000	(309,500,000)
Amount of capital and surplus available for distribution as dividends	432,500,000	557,200,000
GRIL | Ireland
Increase (Decrease) in Common Stock [Roll Forward]
Minimum net worth requirement	9,900,000	9,900,000
Statutory capital and surplus	52,900,000	52,400,000
Net income (loss)	(3,700,000)	3,200,000	$ (12,800,000)
Amount of capital and surplus available for distribution as dividends	$ 0	$ 0