CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Limited Partners' Capital	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest	Total
Balance at Dec. 31, 2014	$ 580,234	$ (15,456)	$ 453,496	$ 1,018,274
Balance (in units) at Dec. 31, 2014	59,863,000
Comprehensive income:
Net income	$ 211,312		92,846	304,158
Actuarially determined long-term liability adjustments		581	709	1,290
COMPREHENSIVE INCOME				305,448
Settlement of Directors Deferred Compensation	(177)			(177)
Vesting of ARLP deferred compensation plans (Note 14)			(2,719)	(2,719)
Common unit-based compensation	223		12,631	12,854
Contribution by limited partner - affiliate (Note 18)	1,500			1,500
Contributions to consolidated company from affiliate noncontrolling interest (Note 10)			2,147	2,147
Distributions on ARLP common unit-based compensation			(2,627)	(2,627)
Distributions to AHGP Partners	(225,833)			(225,833)
Distributions paid by consolidated partnership to noncontrolling interest			(114,735)	(114,735)
Balance at Dec. 31, 2015	$ 567,259	(14,875)	441,748	994,132
Balance (in units) at Dec. 31, 2015	59,863,000
Comprehensive income:
Net income	$ 185,934		150,619	336,553
Actuarially determined long-term liability adjustments		(1,675)	(2,308)	(3,983)
COMPREHENSIVE INCOME				332,570
Settlement of Directors Deferred Compensation	(218)			(218)
Vesting of ARLP deferred compensation plans (Note 14)			(1,336)	(1,336)
Common unit-based compensation	344		13,885	14,229
Contribution by limited partner - affiliate (Note 18)	1,000			1,000
Contributions to consolidated company from affiliate noncontrolling interest (Note 10)			3,014	3,014
Distributions to affiliate noncontrolling interest from consolidated company (Note 10)			(189)	(189)
Distributions on ARLP common unit-based compensation			(3,355)	(3,355)
Distributions to AHGP Partners	(156,242)			(156,242)
Distributions paid by consolidated partnership to noncontrolling interest			(85,956)	(85,956)
Balance at Dec. 31, 2016	$ 598,077	(16,550)	516,122	$ 1,097,649
Balance (in units) at Dec. 31, 2016	59,863,000			59,863,000
Comprehensive income:
Net income	$ 185,988		116,270	$ 302,258
Actuarially determined long-term liability adjustments		(9,082)	(4,318)	(13,400)
Reclassification resulting from the Exchange Transaction		(9,188)	9,188
COMPREHENSIVE INCOME				288,858
Settlement of Directors Deferred Compensation	(26)			(26)
Vesting of ARLP deferred compensation plans (Note 14)			(2,988)	(2,988)
Exchange Transaction fees	(4,612)			(4,612)
Common unit-based compensation	(47)		12,326	12,279
Contribution by limited partner - affiliate (Note 18)	1,000			1,000
Contributions to consolidated company from affiliate noncontrolling interest (Note 10)			251	251
Distributions to affiliate noncontrolling interest from consolidated company (Note 10)			(1,016)	(1,016)
Distributions on ARLP common unit-based compensation			(3,248)	(3,248)
Distributions to AHGP Partners	(153,549)			(153,549)
Distributions paid by consolidated partnership to noncontrolling interest			(81,725)	(81,725)
Balance at Dec. 31, 2017	$ 626,831	$ (34,820)	$ 560,862	$ 1,152,873
Balance (in units) at Dec. 31, 2017	59,863,000			59,863,000