INCOME TAXES - Reconciliations of the income tax (benefit) expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliations of the income tax (benefit) expense
Provision at statutory rate	$ (1,323,834)	$ 282,066	$ 312,795
Effect of state taxes	(60,634)	15,826	14,226
Revision of previous balances	5,997
Other permanent differences	5,035	805	1,990
Total income tax expense (benefits)	$ (1,373,436)	$ 298,697	$ 329,011