SUPPLEMENTAL CONSOLIDATING FINANCIAL INFORMATION - Supplemental Consolidating Statement of Operations Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 287,956	$ 162,499	$ 468,159	$ 323,947
Costs, expenses and other:
Cost of sales	248,389	130,528	387,019	260,949
Depreciation, depletion and amortization	24,479	15,397	40,538	29,823
Selling and administrative	28,709	11,969	42,040	23,855
Heritage health benefit expenses	3,388	3,109	6,932	7,060
Loss (gain) on sales of assets	(43)	(74)	(5)	(308)
Restructuring charges	7,543	0	7,941	0
Derivative loss	5,930	0	5,930	0
Income from equity affiliates	(799)	0	(799)	0
Other operating loss (income)	0	(10,405)	151	(15,142)
Total costs, expenses and other	317,596	150,524	489,747	306,237
Operating income (loss)	(29,640)	11,975	(21,588)	17,710
Other income (expense):
Interest expense	(21,786)	(10,076)	(42,584)	(20,236)
Loss on extinguishment of debt	(12,635)	(64)	(12,635)	(64)
Interest income	1,582	280	1,884	577
Gain (loss) on foreign exchange	2,649	0	(4,141)	0
Other income	483	130	576	198
Total other income (expense)	(29,707)	(9,730)	(56,900)	(19,525)
Income (loss) before income taxes and income of consolidated subsidiaries	(59,347)	2,245	(78,488)	(1,815)
Equity in income of subsidiaries	0	0	0	0
Income (loss) before income taxes	(59,347)	2,245	(78,488)	(1,815)
Income tax expense (benefit)	3,807	28	3,697	55
Net income (loss)	(63,154)	2,217	(82,185)	(1,870)
Less net income attributable to noncontrolling interest	0	2,499	0	797
Net income (loss) attributable to the Parent company	(63,154)	(282)	(82,185)	(2,667)
Parent/ Issuer
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0	0	0
Costs, expenses and other:
Cost of sales	(247)	(372)	(471)	(770)
Depreciation, depletion and amortization	79	94	156	187
Selling and administrative	12,003	4,259	16,968	8,207
Heritage health benefit expenses	3,178	2,844	6,504	6,533
Loss (gain) on sales of assets	0	0	0	0
Restructuring charges	796		796
Derivative loss	0		0
Income from equity affiliates	0		0
Other operating loss (income)		0	0	0
Total costs, expenses and other	15,809	6,825	23,953	14,157
Operating income (loss)	(15,809)	(6,825)	(23,953)	(14,157)
Other income (expense):
Interest expense	(18,609)	(7,591)	(37,282)	(15,175)
Loss on extinguishment of debt	(63)	(64)	(62)	(64)
Interest income	145	46	269	76
Gain (loss) on foreign exchange	1,557		(5,233)
Other income	0	2	0	0
Total other income (expense)	(16,970)	(7,607)	(42,308)	(15,163)
Income (loss) before income taxes and income of consolidated subsidiaries	(32,779)	(14,432)	(66,261)	(29,320)
Equity in income of subsidiaries	(30,462)	16,648	(16,148)	27,450
Income (loss) before income taxes	(63,241)	2,216	(82,409)	(1,870)
Income tax expense (benefit)	(87)	(1)	(224)	0
Net income (loss)	(63,154)	2,217	(82,185)	(1,870)
Less net income attributable to noncontrolling interest	0	2,499		797
Net income (loss) attributable to the Parent company	(63,154)	(282)	(82,185)	(2,667)
Co-Issuer
Condensed Financial Statements, Captions [Line Items]
Revenues	21,803	23,162	43,815	42,498
Costs, expenses and other:
Cost of sales	21,592	14,901	38,046	31,856
Depreciation, depletion and amortization	2,485	2,551	5,009	5,082
Selling and administrative	1,169	872	2,062	1,726
Heritage health benefit expenses	0	0	0	0
Loss (gain) on sales of assets	0	0	0	0
Restructuring charges	101		499
Derivative loss	5,930		5,930
Income from equity affiliates	0		0
Other operating loss (income)		0	0	0
Total costs, expenses and other	31,277	18,324	51,546	38,664
Operating income (loss)	(9,474)	4,838	(7,731)	3,834
Other income (expense):
Interest expense	(74)	(10)	(118)	(20)
Loss on extinguishment of debt	0	0	0	0
Interest income	4	5	7	15
Gain (loss) on foreign exchange	0		0
Other income	0	0	0	0
Total other income (expense)	(70)	(5)	(111)	(5)
Income (loss) before income taxes and income of consolidated subsidiaries	(9,544)	4,833	(7,842)	3,829
Equity in income of subsidiaries	0	0	0	0
Income (loss) before income taxes	(9,544)	4,833	(7,842)	3,829
Income tax expense (benefit)	0	0	0	0
Net income (loss)	(9,544)	4,833	(7,842)	3,829
Less net income attributable to noncontrolling interest	0	0		0
Net income (loss) attributable to the Parent company	(9,544)	4,833	(7,842)	3,829
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenues	266,153	134,449	424,351	274,187
Costs, expenses and other:
Cost of sales	227,044	113,640	349,389	223,417
Depreciation, depletion and amortization	21,915	12,753	35,373	24,554
Selling and administrative	15,921	7,232	23,783	14,680
Heritage health benefit expenses	0	0	0	0
Loss (gain) on sales of assets	(43)	(74)	(5)	(308)
Restructuring charges	6,646		6,646
Derivative loss	0		0
Income from equity affiliates	(799)		(799)
Other operating loss (income)		(10,405)	150	(15,142)
Total costs, expenses and other	270,684	123,146	414,537	247,201
Operating income (loss)	(4,531)	11,303	9,814	26,986
Other income (expense):
Interest expense	(3,111)	(2,479)	(5,199)	(5,048)
Loss on extinguishment of debt	(12,571)	0	(12,572)	0
Interest income	1,433	232	1,608	493
Gain (loss) on foreign exchange	1,092		1,092
Other income	483	130	576	200
Total other income (expense)	(12,674)	(2,117)	(14,495)	(4,355)
Income (loss) before income taxes and income of consolidated subsidiaries	(17,205)	9,186	(4,681)	22,631
Equity in income of subsidiaries	0	0	0	0
Income (loss) before income taxes	(17,205)	9,186	(4,681)	22,631
Income tax expense (benefit)	(74)	1,139	5,041	4,458
Net income (loss)	(17,131)	8,047	(9,722)	18,173
Less net income attributable to noncontrolling interest	0	0		0
Net income (loss) attributable to the Parent company	(17,131)	8,047	(9,722)	18,173
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenues	0	9,538	(7)	20,889
Costs, expenses and other:
Cost of sales	0	7,009	55	20,073
Depreciation, depletion and amortization	0	0	0	0
Selling and administrative	(384)	(394)	(773)	(758)
Heritage health benefit expenses	210	265	428	527
Loss (gain) on sales of assets	0	0	0	0
Restructuring charges	0		0
Derivative loss	0		0
Income from equity affiliates	0		0
Other operating loss (income)		0	1	0
Total costs, expenses and other	(174)	6,880	(289)	19,842
Operating income (loss)	174	2,658	282	1,047
Other income (expense):
Interest expense	(1)	(5)	0	(10)
Loss on extinguishment of debt	(1)	0	(1)	0
Interest income	0	6	15	10
Gain (loss) on foreign exchange	0		0
Other income	0	(2)	0	(2)
Total other income (expense)	(2)	(1)	14	(2)
Income (loss) before income taxes and income of consolidated subsidiaries	172	2,657	296	1,045
Equity in income of subsidiaries	0	0	0	0
Income (loss) before income taxes	172	2,657	296	1,045
Income tax expense (benefit)	1	0	0	0
Net income (loss)	171	2,657	296	1,045
Less net income attributable to noncontrolling interest	0	0		0
Net income (loss) attributable to the Parent company	171	2,657	296	1,045
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Revenues	0	(4,650)	0	(13,627)
Costs, expenses and other:
Cost of sales	0	(4,650)	0	(13,627)
Depreciation, depletion and amortization	0	(1)	0	0
Selling and administrative	0	0	0	0
Heritage health benefit expenses	0	0	0	0
Loss (gain) on sales of assets	0	0	0	0
Restructuring charges	0		0
Derivative loss	0		0
Income from equity affiliates	0		0
Other operating loss (income)		0	0	0
Total costs, expenses and other	0	(4,651)	0	(13,627)
Operating income (loss)	0	1	0	0
Other income (expense):
Interest expense	9	9	15	17
Loss on extinguishment of debt	0	0	0	0
Interest income	0	(9)	(15)	(17)
Gain (loss) on foreign exchange	0		0
Other income	0	0	0	0
Total other income (expense)	9	0	0	0
Income (loss) before income taxes and income of consolidated subsidiaries	9	1	0	0
Equity in income of subsidiaries	30,462	(16,648)	16,148	(27,450)
Income (loss) before income taxes	30,471	(16,647)	16,148	(27,450)
Income tax expense (benefit)	3,967	(1,110)	(1,120)	(4,403)
Net income (loss)	26,504	(15,537)	17,268	(23,047)
Less net income attributable to noncontrolling interest	0	0		0
Net income (loss) attributable to the Parent company	$ 26,504	$ (15,537)	$ 17,268	$ (23,047)