Subsidiary Guarantors (Schedule of Consolidating Statements Of Operations) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended	9 Months Ended
	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2013	Jan. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 115,002			$ 114,578		$ 356,531	$ 371,637
Operating expenses:
Cost of operations	84,168			81,398		254,417	253,248
General and administration	14,480			13,933		43,788	46,202
Depreciation and amortization	14,045			14,827		43,433	44,394
Severance and reorganization costs	1,636				1,793	3,463
Legal settlement							1,359
Expense from divestiture, acquisition and financing costs	372					1,003
Development project cost							131
Loss on divestiture	353					353
Total operating expenses	115,054			110,158		346,457	345,334
Operating income (loss)	(52)			4,420		10,074	26,303
Other expense (income), net:
Interest income	(50)			(20)		(68)	(32)
Interest expense	9,407			11,528		32,958	33,897
Loss (income) from equity method investments	1,436			6,383		3,311	10,163
Loss (gain) on derivative instruments	(24)					3,871
Impairment of equity method investment				10,680			10,680
Loss on debt extinguishment	5,914					15,584
Other income	(298)			(117)		(737)	(549)
Other expense, net	16,385			28,454		54,919	54,159
Income (loss) from continuing operations before income taxes	(16,437)			(24,034)		(44,845)	(27,856)
Provision (benefit) for income taxes	(4,963)			601		(3,899)	1,330
Net income (loss)	(11,474)			(24,635)		(40,946)	(28,461)
Income (loss) from continuing operations	(11,474)			(24,635)		(40,946)	(29,186)
Less: Net income (loss) attributable to noncontrolling interest	(67)					(199)
operations
Gain on disposal of discontinued operations, net of tax		79	646				725
Net income (loss) attributable to common stockholders	(11,407)			(24,635)		(40,747)	(28,461)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues
Operating expenses:
Cost of operations	12			20		4	49
General and administration	705			8		(60)	421
Depreciation and amortization	236			367		770	1,041
Severance and reorganization costs	81					1,766
Legal settlement							1,000
Expense from divestiture, acquisition and financing costs						303
Total operating expenses	1,034			395		2,783	2,511
Operating income (loss)	(1,034)			(395)		(2,783)	(2,511)
Other expense (income), net:
Interest income	(8,275)			(9,798)		(24,515)	(29,514)
Interest expense	9,422			11,523		33,000	33,982
Loss (income) from equity method investments	8,480			21,940		14,324	20,385
Loss (gain) on derivative instruments	(24)					3,871
Loss on debt extinguishment	5,914					15,584
Other income	(181)			(26)		(401)	(233)
Other expense, net	15,336			23,639		41,863	24,620
Income (loss) from continuing operations before income taxes	(16,370)			(24,034)		(44,646)	(27,131)
Provision (benefit) for income taxes	(4,963)			601		(3,899)	1,330
Net income (loss)	(11,407)			(24,635)		(40,747)	(28,461)
Income (loss) from continuing operations							(28,461)
operations
Net income (loss) attributable to common stockholders	(11,407)			(24,635)		(40,747)	(28,461)
Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	114,299			114,578		355,383	371,637
Operating expenses:
Cost of operations	83,487			81,377		253,119	253,196
General and administration	13,748			13,924		43,791	45,780
Depreciation and amortization	13,629			14,460		42,422	43,353
Severance and reorganization costs	1,555					1,697
Legal settlement							359
Expense from divestiture, acquisition and financing costs	372					700
Development project cost							131
Loss on divestiture	353					353
Total operating expenses	113,144			109,761		342,082	342,819
Operating income (loss)	1,155			4,817		13,301	28,818
Other expense (income), net:
Interest income	(49)			(19)		(64)	(26)
Interest expense	8,259			9,802		24,469	29,423
Loss (income) from equity method investments	43			(26)		(14)	(27)
Other income	(117)			(91)		(336)	(316)
Other expense, net	8,136			9,666		24,055	29,054
Income (loss) from continuing operations before income taxes	(6,981)			(4,849)		(10,754)	(236)
Net income (loss)	(6,981)			(4,849)		(10,754)	(489)
Income (loss) from continuing operations							(236)
operations
Gain on disposal of discontinued operations, net of tax							725
Net income (loss) attributable to common stockholders	(6,981)			(4,849)		(10,754)	489
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	703					1,148
Operating expenses:
Cost of operations	669			1		1,294	3
General and administration	27			1		57	1
Depreciation and amortization	180					241
Expense from divestiture, acquisition and financing costs
Total operating expenses	876			2		1,592	4
Operating income (loss)	(173)			(2)		(444)	(4)
Other expense (income), net:
Loss (income) from equity method investments	1,393			6,409		3,325	10,190
Impairment of equity method investment				10,680			10,680
Other expense, net	1,393			17,089		3,325	20,870
Income (loss) from continuing operations before income taxes	(1,566)			(17,091)		(3,769)	(20,874)
Net income (loss)	(1,566)			(17,091)		(3,769)	(20,874)
Income (loss) from continuing operations							(20,874)
Less: Net income (loss) attributable to noncontrolling interest	(67)					(199)
operations
Net income (loss) attributable to common stockholders	(1,499)			(17,091)		(3,570)	(20,874)
Elimination [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues
Operating expenses:
Expense from divestiture, acquisition and financing costs
Other expense (income), net:
Interest income	8,274			9,797		24,511	29,508
Interest expense	(8,274)			(9,797)		(24,511)	(29,508)
Loss (income) from equity method investments	(8,480)			(21,940)		(14,324)	(20,385)
Other expense, net	(8,480)			(21,940)		(14,324)	(20,385)
Income (loss) from continuing operations before income taxes	8,480			21,940		14,324	20,385
Net income (loss)	8,480			21,940		14,324	20,385
Income (loss) from continuing operations							20,385
operations
Net income (loss) attributable to common stockholders	$ 8,480			$ 21,940		$ 14,324	$ 20,385