SUPPLEMENTAL CONSOLIDATING FINANCIAL INFORMATION - Supplemental Consolidating Statement of Operations Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 161,448	$ 147,236
Costs, expenses and other:
Cost of sales	130,421	110,763
Depreciation, depletion and amortization	14,426	13,289
Selling and administrative	11,887	13,535
Heritage health benefit expenses	3,951	3,810
Gain (loss) on sales of assets	(234)	38
Other operating income	(4,737)	(3,284)
Total costs, expenses and other	155,714	138,151
Operating income (loss)	5,734	9,085
Other income (expense):
Interest expense	(10,160)	(9,883)
Interest income	297	406
Other income (loss)	70	177
Total other income (expense)	(9,793)	(9,300)
Income (loss) before income taxes and income of consolidated subsidiaries	(4,059)	(215)
Equity in income of subsidiaries	0	0
Loss before income taxes	(4,059)	(215)
Income tax expense (benefit)	28	7
Net income (loss)	(4,087)	(222)
Less net loss attributable to noncontrolling interest	(1,702)	(1,080)
Net income (loss) attributable to the Parent company	(2,385)	858
Parent/ Issuer
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0
Costs, expenses and other:
Cost of sales	0	0
Depreciation, depletion and amortization	94	108
Selling and administrative	3,054	3,067
Heritage health benefit expenses	3,689	3,569
Gain (loss) on sales of assets	0	0
Other operating income	0	0
Total costs, expenses and other	6,837	6,744
Operating income (loss)	(6,837)	(6,744)
Other income (expense):
Interest expense	(7,584)	(6,900)
Interest income	30	50
Other income (loss)	0	52
Total other income (expense)	(7,554)	(6,798)
Income (loss) before income taxes and income of consolidated subsidiaries	(14,391)	(13,542)
Equity in income of subsidiaries	10,304	13,292
Loss before income taxes	(4,087)	(250)
Income tax expense (benefit)	0	(28)
Net income (loss)	(4,087)	(222)
Less net loss attributable to noncontrolling interest	(1,702)	(1,080)
Net income (loss) attributable to the Parent company	(2,385)	858
Co-Issuer
Condensed Financial Statements, Captions [Line Items]
Revenues	19,336	20,722
Costs, expenses and other:
Cost of sales	16,954	14,497
Depreciation, depletion and amortization	2,531	2,498
Selling and administrative	855	937
Heritage health benefit expenses	0	0
Gain (loss) on sales of assets	0	0
Other operating income	0	0
Total costs, expenses and other	20,340	17,932
Operating income (loss)	(1,004)	2,790
Other income (expense):
Interest expense	(10)	(10)
Interest income	10	2
Other income (loss)	0	0
Total other income (expense)	0	(8)
Income (loss) before income taxes and income of consolidated subsidiaries	(1,004)	2,782
Equity in income of subsidiaries	0	0
Loss before income taxes	(1,004)	2,782
Income tax expense (benefit)	0	0
Net income (loss)	(1,004)	2,782
Less net loss attributable to noncontrolling interest	0	0
Net income (loss) attributable to the Parent company	(1,004)	2,782
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenues	50,687	38,191
Costs, expenses and other:
Cost of sales	40,421	25,856
Depreciation, depletion and amortization	5,189	3,779
Selling and administrative	2,637	3,359
Heritage health benefit expenses	0	0
Gain (loss) on sales of assets	(133)	0
Other operating income	(4,737)	(4,812)
Total costs, expenses and other	43,377	28,182
Operating income (loss)	7,310	10,009
Other income (expense):
Interest expense	(74)	(94)
Interest income	44	53
Other income (loss)	92	24
Total other income (expense)	62	(17)
Income (loss) before income taxes and income of consolidated subsidiaries	7,372	9,992
Equity in income of subsidiaries	0	0
Loss before income taxes	7,372	9,992
Income tax expense (benefit)	496	538
Net income (loss)	6,876	9,454
Less net loss attributable to noncontrolling interest	0	0
Net income (loss) attributable to the Parent company	6,876	9,454
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenues	100,401	95,416
Costs, expenses and other:
Cost of sales	82,022	77,503
Depreciation, depletion and amortization	6,612	6,904
Selling and administrative	5,341	7,699
Heritage health benefit expenses	262	241
Gain (loss) on sales of assets	(101)	38
Other operating income	0	1
Total costs, expenses and other	94,136	92,386
Operating income (loss)	6,265	3,030
Other income (expense):
Interest expense	(2,500)	(2,899)
Interest income	221	321
Other income (loss)	(22)	101
Total other income (expense)	(2,301)	(2,477)
Income (loss) before income taxes and income of consolidated subsidiaries	3,964	553
Equity in income of subsidiaries	0	0
Loss before income taxes	3,964	553
Income tax expense (benefit)	2,823	1,619
Net income (loss)	1,141	(1,066)
Less net loss attributable to noncontrolling interest	0	0
Net income (loss) attributable to the Parent company	1,141	(1,066)
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Revenues	(8,976)	(7,093)
Costs, expenses and other:
Cost of sales	(8,976)	(7,093)
Depreciation, depletion and amortization	0	0
Selling and administrative	0	(1,527)
Heritage health benefit expenses	0	0
Gain (loss) on sales of assets	0	0
Other operating income	0	1,527
Total costs, expenses and other	(8,976)	(7,093)
Operating income (loss)	0	0
Other income (expense):
Interest expense	8	20
Interest income	(8)	(20)
Other income (loss)	0	0
Total other income (expense)	0	0
Income (loss) before income taxes and income of consolidated subsidiaries	0	0
Equity in income of subsidiaries	(10,304)	(13,292)
Loss before income taxes	(10,304)	(13,292)
Income tax expense (benefit)	(3,291)	(2,122)
Net income (loss)	(7,013)	(11,170)
Less net loss attributable to noncontrolling interest	0	0
Net income (loss) attributable to the Parent company	$ (7,013)	$ (11,170)