Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Per Share data, unless otherwise specified	Total	Common Stock [Member]	Capital in Excess of Par Value	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income (Loss)	Common Stock in Treasury	Total CONSOL Energy Inc. Stockholders' Equity	Non-Controlling Interest
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2012	$ 3,953,745	$ 2,284	$ 2,296,908	$ 2,402,551	$ (747,342)	$ (609)	$ 3,953,792	$ (47)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	(1,821)	0	0	(1,564)	0	0	(1,564)	(257)
Other Comprehensive Income (Loss), Net of Tax	4,449	0	0	0	4,449	0	4,449	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	2,628	0	0	(1,564)	4,449	0	2,885	(257)
Proceeds from Issuance of Common Stock	909	5	904	0	0	0	909	0
Stock Issued During Period, Value, Treasury Stock Reissued	(7,459)	0	0	(7,459)	0	0	(7,459)	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	(3,658)	0	(3,658)	0	0	0	(3,658)	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	26,069	0	26,069	0	0	0	26,069	0
Dividends Paid Per Share	$ 0.000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Mar. 31, 2013	$ 3,972,234	$ 2,289	$ 2,320,223	$ 2,393,528	$ (742,893)	$ (609)	$ 3,972,538	$ (304)