Guarantor and Non-guarantor Financial Statements, Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 1,820	$ 1,099	$ 7,571	$ 2,821
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			25,326	24,907
Amortization - deferred financing costs and debt discount			1,859	1,859
Amortization - other intangible assets			6,174	6,097
(Gain) loss on disposal of assets			240	669
Deferred income taxes			(4,864)	(592)
Non-cash stock-based compensation	698	622	2,147	1,831
Equity in earnings of subsidiaries and affiliates			0	0
Change in other operating items			(7,358)	(29,318)
Net cash provided by operating activities			31,095	8,274
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment			(15,879)	(20,734)
Proceeds from notes receivable			0	0
Payments on notes receivable			0	0
Other			(1,903)	564
Net cash used in investing activities			(17,782)	(20,170)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of notes payable			(23,000)	(10,000)
Proceeds from notes payable			21,000	10,000
Principal payments on capital leases			(1,937)	0
Other			(24)	0
Net cash used in financing activities			(3,961)	0
Net increase in cash and cash equivalents			9,352	(11,896)
Cash and cash equivalents, beginning of period			29,773	33,426
Cash and cash equivalents, end of period	39,125	21,530	39,125	21,530
Eliminations [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	(10,386)	(5,796)	(33,007)	(20,788)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			0	0
Amortization - deferred financing costs and debt discount			0	0
Amortization - other intangible assets			0	0
(Gain) loss on disposal of assets			0	0
Deferred income taxes			0	0
Non-cash stock-based compensation			0	0
Equity in earnings of subsidiaries and affiliates			31,950	20,377
Change in other operating items			1,057	411
Net cash provided by operating activities			0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment			0	0
Proceeds from notes receivable			58,600	103,928
Payments on notes receivable			(81,603)	(69,616)
Other			0	0
Net cash used in investing activities			(23,003)	34,312
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of notes payable			81,603	69,616
Proceeds from notes payable			(58,600)	(103,928)
Principal payments on capital leases			0
Other			0	0
Net cash used in financing activities			23,003	(34,312)
Net increase in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	0	0	0	0
Parent [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	1,820	1,099	7,571	2,821
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			8,302	8,335
Amortization - deferred financing costs and debt discount			1,859	1,859
Amortization - other intangible assets			6,048	5,971
(Gain) loss on disposal of assets			256	580
Deferred income taxes			(5,299)	(2,195)
Non-cash stock-based compensation			2,147	1,831
Equity in earnings of subsidiaries and affiliates			(31,950)	(20,377)
Change in other operating items			44,418	14,837
Net cash provided by operating activities			33,352	13,662
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment			(7,499)	(8,350)
Proceeds from notes receivable			3,518	36,698
Payments on notes receivable			(26,268)	(34,517)
Other			0	(671)
Net cash used in investing activities			(30,249)	(6,840)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of notes payable			(18,053)	(42,775)
Proceeds from notes payable			15,312	19,041
Principal payments on capital leases			0
Other			3,140	0
Net cash used in financing activities			399	(23,734)
Net increase in cash and cash equivalents			3,502	(16,912)
Cash and cash equivalents, beginning of period			22,710	31,018
Cash and cash equivalents, end of period	26,212	14,106	26,212	14,106
Guarantor Subsidiaries [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	6,721	4,254	24,632	14,763
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			14,142	13,446
Amortization - deferred financing costs and debt discount			0	0
Amortization - other intangible assets			126	126
(Gain) loss on disposal of assets			39	62
Deferred income taxes			435	925
Non-cash stock-based compensation			0	0
Equity in earnings of subsidiaries and affiliates			0	0
Change in other operating items			(52,797)	(41,354)
Net cash provided by operating activities			(13,423)	(12,032)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment			(7,449)	(11,977)
Proceeds from notes receivable			(28,217)	(106,680)
Payments on notes receivable			75,191	71,408
Other			(1,903)	1,235
Net cash used in investing activities			37,622	(46,014)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of notes payable			(86,550)	(36,841)
Proceeds from notes payable			64,288	94,887
Principal payments on capital leases			(1,937)
Other			0	0
Net cash used in financing activities			(24,199)	58,046
Net increase in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	0	0	0	0
Non-guarantor Subsidiaries [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	3,665	1,542	8,375	6,025
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			2,882	3,126
Amortization - deferred financing costs and debt discount			0	0
Amortization - other intangible assets			0	0
(Gain) loss on disposal of assets			(55)	27
Deferred income taxes			0	678
Non-cash stock-based compensation			0	0
Equity in earnings of subsidiaries and affiliates			0	0
Change in other operating items			(36)	(3,212)
Net cash provided by operating activities			11,166	6,644
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment			(931)	(407)
Proceeds from notes receivable			(33,901)	(33,946)
Payments on notes receivable			32,680	32,725
Other			0	0
Net cash used in investing activities			(2,152)	(1,628)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of notes payable			0	0
Proceeds from notes payable			0	0
Principal payments on capital leases			0
Other			(3,164)	0
Net cash used in financing activities			(3,164)	0
Net increase in cash and cash equivalents			5,850	5,016
Cash and cash equivalents, beginning of period			7,063	2,408
Cash and cash equivalents, end of period	$ 12,913	$ 7,424	$ 12,913	$ 7,424