EARNINGS PER SHARE - Reconciliation of weighted average shares outstanding (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
EARNINGS PER SHARE
Net (loss) income available for stockholders:	$ (34,055)	$ 63,283	$ (26,507)	$ 102,671
Less: Dividends paid	(10,837)	(22,898)	(33,599)	(45,883)
(Over distributed loss) Undistributed earnings	$ (44,892)	$ 40,385	$ (60,106)	$ 56,788
Basic shares outstanding:
Common stock	208,156	211,611	210,195	211,522
Restricted shares of common stock	4,442	3,613	3,391	3,677
Basic shares outstanding, Total	212,598	215,224	213,586	215,199
Diluted shares outstanding:
Common stock	208,156	211,611	210,195	211,522
Dilutive effect of stock based awards		1,014		1,081
Diluted shares outstanding excluding restricted shares of common stock, Total	208,156	212,625	210,195	212,603
Restricted shares of common stock	4,442	3,613	3,391	3,677
Diluted shares outstanding, Total	212,598	216,238	213,586	216,280