Selected Consolidated Financial Statements of Parent, Guarantors, Canada Company and Non-Guarantors (Details 3) (USD $) In Thousands, unless otherwise specified	1 Months Ended					3 Months Ended
	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Mar. 31, 2012	Mar. 31, 2011
Consolidating financial statements
Cash Flows from Operating Activities-Continuing Operations						$ 79,059	$ 110,418
Cash Flows from Operating Activities-Discontinued Operations						(4,175)	8,919
Cash Flows from Operating Activities						74,884	119,337
Cash Flows from Investing Activities:
Capital expenditures						(55,916)	(52,208)
Cash paid for acquisitions, net of cash acquired						(8,818)	(34,705)
Investment in restricted cash						(2)	(2)
Additions to customer relationship and acquisition costs						(3,008)	(2,893)
Investment in joint ventures							(50)
Proceeds from sales of property and equipment and other, net						1,853	166
Cash Flows from Investing Activities-Continuing Operations						(65,891)	(89,692)
Cash Flows from Investing Activities-Discontinued Operations						(1,141)	(9,299)
Cash Flows from Investing Activities						(67,032)	(98,991)
Cash Flows from Financing Activities:
Repayment of revolving credit and term loan facilities and other debt						(635,539)	(428,548)
Proceeds from revolving credit and term loan facilities and other debt						701,105	607,418
Early retirement of senior subordinated notes							(231,255)
Debt financing (repayment to) and equity contribution from (distribution to) noncontrolling interests, net						191	131
Stock repurchases						(38,052)	(10,970)
Parent cash dividends	(42,791)	(43,180)	(46,877)	(50,694)	(37,601)	(43,180)	(37,514)
Proceeds from exercise of stock options and employee stock purchase plan						1,321	9,164
Excess tax benefits from stock-based compensation						190	1,017
Payment of debt financing costs						(93)
Cash Flows from Financing Activities-Continuing Operations						(14,057)	(90,557)
Cash Flows from Financing Activities-Discontinued Operations						(39)	46
Cash Flows from Financing Activities						(14,096)	(90,511)
Effect of Exchange Rates on Cash and Cash Equivalents						4,692	1,289
(Decrease) Increase in Cash and Cash Equivalents						(1,552)	(68,876)
Cash and Cash Equivalents, Beginning of Period	178,293	179,845			189,817	179,845	258,693
Cash and Cash Equivalents, End of Period						178,293	189,817
Parent
Consolidating financial statements
Cash Flows from Operating Activities-Continuing Operations						(40,455)	(53,891)
Cash Flows from Operating Activities						(40,455)	(53,891)
Cash Flows from Investing Activities:
Intercompany loans to subsidiaries						116,821	132,655
Investment in subsidiaries							(1,000)
Investment in restricted cash						(2)	(2)
Cash Flows from Investing Activities-Continuing Operations						116,819	131,653
Cash Flows from Investing Activities						116,819	131,653
Cash Flows from Financing Activities:
Repayment of revolving credit and term loan facilities and other debt							(361,015)
Proceeds from revolving credit and term loan facilities and other debt							540,000
Early retirement of senior subordinated notes							(231,255)
Stock repurchases						(38,052)	(10,970)
Parent cash dividends						(43,180)	(37,514)
Proceeds from exercise of stock options and employee stock purchase plan						1,321	9,164
Excess tax benefits from stock-based compensation						190	1,017
Cash Flows from Financing Activities-Continuing Operations						(79,721)	(90,573)
Cash Flows from Financing Activities						(79,721)	(90,573)
(Decrease) Increase in Cash and Cash Equivalents						(3,357)	(12,811)
Cash and Cash Equivalents, Beginning of Period		3,428				3,428	13,909
Cash and Cash Equivalents, End of Period						71	1,098
Guarantors
Consolidating financial statements
Cash Flows from Operating Activities-Continuing Operations						100,211	142,876
Cash Flows from Operating Activities-Discontinued Operations						(2,415)	8,146
Cash Flows from Operating Activities						97,796	151,022
Cash Flows from Investing Activities:
Capital expenditures						(31,371)	(32,028)
Cash paid for acquisitions, net of cash acquired						(8,818)	(4,971)
Intercompany loans to subsidiaries						(19,330)	(24,524)
Investment in subsidiaries							(1,000)
Additions to customer relationship and acquisition costs						(2,523)	(2,095)
Proceeds from sales of property and equipment and other, net						1,885	119
Cash Flows from Investing Activities-Continuing Operations						(60,157)	(64,499)
Cash Flows from Investing Activities-Discontinued Operations						(25)	(9,115)
Cash Flows from Investing Activities						(60,182)	(73,614)
Cash Flows from Financing Activities:
Repayment of revolving credit and term loan facilities and other debt						(623,221)	(10,435)
Proceeds from revolving credit and term loan facilities and other debt						700,000
Intercompany loans from parent						(116,998)	(135,177)
Equity contribution from parent							1,000
Payment of debt financing costs						(93)
Cash Flows from Financing Activities-Continuing Operations						(40,312)	(144,612)
Cash Flows from Financing Activities						(40,312)	(144,612)
(Decrease) Increase in Cash and Cash Equivalents						(2,698)	(67,204)
Cash and Cash Equivalents, Beginning of Period		10,750				10,750	121,584
Cash and Cash Equivalents, End of Period						8,052	54,380
Canada Company
Consolidating financial statements
Cash Flows from Operating Activities-Continuing Operations						4,108	5,183
Cash Flows from Operating Activities						4,108	5,183
Cash Flows from Investing Activities:
Capital expenditures						(2,828)	(2,262)
Cash paid for acquisitions, net of cash acquired							(58)
Additions to customer relationship and acquisition costs						(62)	(121)
Proceeds from sales of property and equipment and other, net						5	10
Cash Flows from Investing Activities-Continuing Operations						(2,885)	(2,431)
Cash Flows from Investing Activities						(2,885)	(2,431)
Cash Flows from Financing Activities:
Repayment of revolving credit and term loan facilities and other debt						(715)	(735)
Intercompany loans from parent						(2,860)	(2,067)
Cash Flows from Financing Activities-Continuing Operations						(3,575)	(2,802)
Cash Flows from Financing Activities						(3,575)	(2,802)
Effect of Exchange Rates on Cash and Cash Equivalents						1,623	1,132
(Decrease) Increase in Cash and Cash Equivalents						(729)	1,082
Cash and Cash Equivalents, Beginning of Period		68,907				68,907	37,652
Cash and Cash Equivalents, End of Period						68,178	38,734
Non-Guarantors
Consolidating financial statements
Cash Flows from Operating Activities-Continuing Operations						15,195	16,250
Cash Flows from Operating Activities-Discontinued Operations						(1,760)	773
Cash Flows from Operating Activities						13,435	17,023
Cash Flows from Investing Activities:
Capital expenditures						(21,717)	(17,918)
Cash paid for acquisitions, net of cash acquired							(29,676)
Additions to customer relationship and acquisition costs						(423)	(677)
Investment in joint ventures							(50)
Proceeds from sales of property and equipment and other, net						(37)	37
Cash Flows from Investing Activities-Continuing Operations						(22,177)	(48,284)
Cash Flows from Investing Activities-Discontinued Operations						(1,116)	(184)
Cash Flows from Investing Activities						(23,293)	(48,468)
Cash Flows from Financing Activities:
Repayment of revolving credit and term loan facilities and other debt						(11,603)	(56,363)
Proceeds from revolving credit and term loan facilities and other debt						1,105	67,418
Debt financing (repayment to) and equity contribution from (distribution to) noncontrolling interests, net						191	131
Intercompany loans from parent						22,367	29,113
Equity contribution from parent							1,000
Cash Flows from Financing Activities-Continuing Operations						12,060	41,299
Cash Flows from Financing Activities-Discontinued Operations						(39)	46
Cash Flows from Financing Activities						12,021	41,345
Effect of Exchange Rates on Cash and Cash Equivalents						3,069	157
(Decrease) Increase in Cash and Cash Equivalents						5,232	10,057
Cash and Cash Equivalents, Beginning of Period		96,760				96,760	85,548
Cash and Cash Equivalents, End of Period						101,992	95,605
Eliminations
Cash Flows from Investing Activities:
Intercompany loans to subsidiaries						(97,491)	(108,131)
Investment in subsidiaries							2,000
Cash Flows from Investing Activities-Continuing Operations						(97,491)	(106,131)
Cash Flows from Investing Activities						(97,491)	(106,131)
Cash Flows from Financing Activities:
Intercompany loans from parent						97,491	108,131
Equity contribution from parent							(2,000)
Cash Flows from Financing Activities-Continuing Operations						97,491	106,131
Cash Flows from Financing Activities						$ 97,491	$ 106,131