Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows - operating activities:
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	$ 148,886	$ 133,671	$ (82,684)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	31,204	27,426	25,498
Amortization of identifiable intangible assets	29,762	26,350	16,417
Provision for (recovery of) doubtful accounts	1,163	2,238	(5,126)
Deferred income taxes	6,626	8,826	(15,390)
Gain on sale of discontinued operation, net of income taxes	0	(9,127)	0
Gain on sale of equity investments	0	0	(12,409)
Loss on sale of property, plant and equipment	272	592	127
Excess tax benefits from share-based compensation	(7,083)	(3,619)	(1,474)
Equity income from unconsolidated entities	(930)	(1,301)	(843)
Non-cash expense for amortization of debt issuance costs	1,212	2,438	2,703
Non-cash income from contingent consideration arrangements	(6,381)	(2,798)	(394)
Non-cash expense for impairment of goodwill and identifiable intangible assets	0	3,795	246,081
Non-cash share-based compensation expense	6,766	5,447	5,742
Supplemental defined benefit plan contribution	0	0	(25,916)
Distributions from unconsolidated entities	887	606	958
Increase in accounts receivable	(12,852)	(75,529)	(8,342)
(Increase) decrease in inventories	(5,597)	(10,549)	2,118
Decrease (increase) in costs and estimated earnings in excess of billings on uncompleted contracts	24,126	(33,816)	8,757
Increase in accounts payable	5,425	34,727	16,992
Decrease in billings in excess of costs and estimated earnings on uncompleted contracts	(62,533)	(16,278)	(73,714)
Increase (decrease) in accrued payroll and benefits and other accrued expenses and liabilities	24,345	49,634	(42,639)
Changes in other assets and liabilities, net	(890)	6,692	13,065
Net cash provided by operating activities	184,408	149,425	69,527
Cash flows - investing activities:
Payments for acquisitions of businesses, net of cash acquired, and related contingent consideration arrangement	(20,613)	(301,306)	(39,902)
Proceeds from sale of discontinued operation, net of cash sold	0	26,627	0
Proceeds from sale of equity investments	0	0	25,570
Proceeds from sale of property, plant and equipment	3,070	1,409	1,032
Purchase of property, plant and equipment	(37,875)	(29,581)	(19,359)
Investments in and advances to unconsolidated entities and joint ventures	0	(28)	(65)
Purchase of short-term investments	(22,433)	(17,639)	0
Maturity of short-term investments	35,305	0	0
Net cash used in investing activities	(42,546)	(320,518)	(32,724)
Cash flows - financing activities:
Proceeds from revolving credit facility	0	0	153,000
Repayments of revolving credit facility	0	0	(3,000)
Net repayments of long-term debt and debt issuance costs	(40)	(4,147)	(200,828)
Repayments of capital lease obligations	(1,978)	(1,095)	(430)
Dividends paid to stockholders	(34,073)	(3,336)	0
Repurchase of common stock	(23,912)	(27,523)	0
Proceeds from exercise of stock options	8,786	5,608	2,818
Payments to satisfy minimum tax withholding	(1,654)	(1,256)	(875)
Issuance of common stock under employee stock purchase plan	2,549	2,310	2,305
Payments for contingent consideration arrangements	(5,748)	(1,118)	0
Distributions to noncontrolling interests	(1,600)	(2,350)	(2,500)
Excess tax benefits from share-based compensation	7,083	3,619	1,474
Net cash used in financing activities	(50,587)	(29,288)	(48,036)
Effect of exchange rate changes on cash and cash equivalents	2,706	867	(4,906)
Increase (decrease) in cash and cash equivalents	93,981	(199,514)	(16,139)
Cash and cash equivalents at beginning of year	511,322	710,836	726,975
Cash and cash equivalents at end of period	$ 605,303	$ 511,322	$ 710,836