Supplemental Guarantor Condensed Consolidating Financial Information - Condensed Statement of Cash Flow (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash Flows from Operating Activities:
Net cash provided by (used for) operating activities	$ (4,880)	$ (4,660)
Cash Flows from Investing Activities:
Capital expenditures	(26,640)	(14,020)
Acquisition of businesses, net of cash acquired	(61,820)	0
Net proceeds from disposition of assets	2,770	1,660
Net cash provided by (used for) inveting activities	(85,690)	(12,360)
Cash Flows from Financing Activities:
Proceeds from sale of common stock	79,040	0
Proceeds from borrowings on term loan facilities	69,530	226,520
Repayments of borrowings on term loan facilities	(69,150)	(248,950)
Proceeds from borrowings on revolving credit facilities and accounts receivable facility	412,900	303,520
Repayments of borrowings on revolving credit facilities and accounts receivable facility	(412,900)	(297,600)
Retirement of senior secured notes	(50,000)	0
Senior secured notes redemption premium and debt financing fees	(4,880)	(6,570)
Distributions to noncontrolling interests	(410)	0
Shares surrendered upon vesting of options and restricted stock awards to cover tax obligations	(990)	(830)
Proceeds from exercise of stock options	5,660	830
Excess tax benefits from stock based compensation	2,130	3,800
Intercompany transfers (to) from subsidiaries	0	0
Net cash provided by (used for) financing activities	30,930	(19,280)
Cash and Cash Equivalents:
(Decrease) Increase for the period	(59,640)	(36,300)
At beginning of period	88,920	46,370
At end of period	29,280	10,070
Parent [Member]
Cash Flows from Operating Activities:
Net cash provided by (used for) operating activities	(41,000)	(12,190)
Cash Flows from Investing Activities:
Capital expenditures	0	0
Acquisition of businesses, net of cash acquired	0
Net proceeds from disposition of assets	0	0
Net cash provided by (used for) inveting activities	0	0
Cash Flows from Financing Activities:
Proceeds from sale of common stock	79,040
Proceeds from borrowings on term loan facilities	0	0
Repayments of borrowings on term loan facilities	0	0
Proceeds from borrowings on revolving credit facilities and accounts receivable facility	0	0
Repayments of borrowings on revolving credit facilities and accounts receivable facility	0	0
Retirement of senior secured notes	(50,000)
Senior secured notes redemption premium and debt financing fees	(4,880)	0
Distributions to noncontrolling interests	0
Shares surrendered upon vesting of options and restricted stock awards to cover tax obligations	(990)	(830)
Proceeds from exercise of stock options	5,660	830
Excess tax benefits from stock based compensation	0	0
Intercompany transfers (to) from subsidiaries	12,170	12,190
Net cash provided by (used for) financing activities	41,000	12,190
Cash and Cash Equivalents:
(Decrease) Increase for the period	0	0
At beginning of period	0	0
At end of period	0	0
Guarantor [Member]
Cash Flows from Operating Activities:
Net cash provided by (used for) operating activities	23,810	(840)
Cash Flows from Investing Activities:
Capital expenditures	(17,340)	(9,490)
Acquisition of businesses, net of cash acquired	(61,820)
Net proceeds from disposition of assets	2,770	1,640
Net cash provided by (used for) inveting activities	(76,390)	(7,850)
Cash Flows from Financing Activities:
Proceeds from sale of common stock	0
Proceeds from borrowings on term loan facilities	0	225,000
Repayments of borrowings on term loan facilities	(6,160)	(248,950)
Proceeds from borrowings on revolving credit facilities and accounts receivable facility	412,900	303,520
Repayments of borrowings on revolving credit facilities and accounts receivable facility	(412,900)	(297,600)
Retirement of senior secured notes	0
Senior secured notes redemption premium and debt financing fees	0	(6,570)
Distributions to noncontrolling interests	(410)
Shares surrendered upon vesting of options and restricted stock awards to cover tax obligations	0	0
Proceeds from exercise of stock options	0	0
Excess tax benefits from stock based compensation	2,130	3,800
Intercompany transfers (to) from subsidiaries	32,180	14,630
Net cash provided by (used for) financing activities	27,740	(6,170)
Cash and Cash Equivalents:
(Decrease) Increase for the period	(24,840)	(14,860)
At beginning of period	33,820	15,070
At end of period	8,980	210
Non-Guarantor [Member]
Cash Flows from Operating Activities:
Net cash provided by (used for) operating activities	12,310	8,370
Cash Flows from Investing Activities:
Capital expenditures	(9,300)	(4,530)
Acquisition of businesses, net of cash acquired	0
Net proceeds from disposition of assets	0	20
Net cash provided by (used for) inveting activities	(9,300)	(4,510)
Cash Flows from Financing Activities:
Proceeds from sale of common stock	0
Proceeds from borrowings on term loan facilities	69,530	1,520
Repayments of borrowings on term loan facilities	(62,990)	0
Proceeds from borrowings on revolving credit facilities and accounts receivable facility	0	0
Repayments of borrowings on revolving credit facilities and accounts receivable facility	0	0
Retirement of senior secured notes	0
Senior secured notes redemption premium and debt financing fees	0	0
Distributions to noncontrolling interests	0
Shares surrendered upon vesting of options and restricted stock awards to cover tax obligations	0	0
Proceeds from exercise of stock options	0	0
Excess tax benefits from stock based compensation	0	0
Intercompany transfers (to) from subsidiaries	(44,350)	(26,820)
Net cash provided by (used for) financing activities	(37,810)	(25,300)
Cash and Cash Equivalents:
(Decrease) Increase for the period	(34,800)	(21,440)
At beginning of period	55,100	31,300
At end of period	20,300	9,860
Eliminations [Member]
Cash Flows from Operating Activities:
Net cash provided by (used for) operating activities	0	0
Cash Flows from Investing Activities:
Capital expenditures	0	0
Acquisition of businesses, net of cash acquired	0
Net proceeds from disposition of assets	0	0
Net cash provided by (used for) inveting activities	0	0
Cash Flows from Financing Activities:
Proceeds from sale of common stock	0
Proceeds from borrowings on term loan facilities	0	0
Repayments of borrowings on term loan facilities	0	0
Proceeds from borrowings on revolving credit facilities and accounts receivable facility	0	0
Repayments of borrowings on revolving credit facilities and accounts receivable facility	0	0
Retirement of senior secured notes	0
Senior secured notes redemption premium and debt financing fees	0	0
Distributions to noncontrolling interests	0
Shares surrendered upon vesting of options and restricted stock awards to cover tax obligations	0	0
Proceeds from exercise of stock options	0	0
Excess tax benefits from stock based compensation	0	0
Intercompany transfers (to) from subsidiaries	0	0
Net cash provided by (used for) financing activities	0	0
Cash and Cash Equivalents:
(Decrease) Increase for the period	0	0
At beginning of period	0	0
At end of period	$ 0	$ 0