Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows - operating activities:
Net income including noncontrolling interests	$ 173,427	$ 127,354	$ 148,886
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	36,524	36,310	31,204
Amortization of identifiable intangible assets	37,966	31,028	29,762
Provision for doubtful accounts	2,918	3,533	1,163
Deferred income taxes	5,748	11,857	6,626
Loss on sale of subsidiary	608	0	0
Gain on sale of building	(11,749)	0	0
(Gain) loss on sale of property, plant and equipment	(4,920)	(903)	272
Excess tax benefits from share-based compensation	(8,264)	(4,624)	(7,083)
Equity income from unconsolidated entities	(1,440)	(1,048)	(930)
Non-cash expense for amortization of debt issuance costs	1,263	1,497	1,212
Non-cash expense (income) from contingent consideration arrangements	606	(6,793)	(6,381)
Non-cash expense for impairment of identifiable intangible assets	1,471	0	0
Non-cash share-based compensation expense	8,121	6,943	6,766
Non-cash expense (income) from changes in unrecognized income tax benefits	2,143	(10,539)	5,946
Distributions from unconsolidated entities	1,767	679	887
Decrease (increase) in accounts receivable	27,409	(3,221)	(12,852)
Decrease (increase) in inventories	5,269	(865)	(5,597)
(Increase) decrease in costs and estimated earnings in excess of billings on uncompleted contracts	(13,010)	2,807	24,126
(Decrease) increase in accounts payable	(25,122)	(12,904)	5,425
Decrease in billings in excess of costs and estimated earnings on uncompleted contracts	(11,868)	(2,793)	(62,533)
Increase (decrease) in accrued payroll and benefits and other accrued expenses and liabilities	32,340	(14,761)	24,345
Changes in other assets and liabilities, net	(14,550)	(13,488)	(6,836)
Net cash provided by operating activities	246,657	150,069	184,408
Cash flows - investing activities:
Payments for acquisitions of businesses, net of cash acquired	0	(454,671)	(20,613)
Proceeds from sale of subsidiary	1,108	0	0
Proceeds from sale of building	11,885	0	0
Proceeds from sale of property, plant and equipment	7,239	2,930	3,070
Purchase of property, plant and equipment	(38,035)	(35,497)	(37,875)
Investments in and advances to unconsolidated entities and joint ventures	(3,865)	(800)	0
Purchase of short-term investments	0	0	(22,433)
Maturity of short-term investments	0	4,616	35,305
Net cash used in investing activities	(21,668)	(483,422)	(42,546)
Cash flows - financing activities:
Proceeds from revolving credit facility	0	250,000	0
Repayments of revolving credit facility	0	(400,000)	0
Borrowings from long-term debt	0	350,000	0
Repayments of long-term debt and debt issuance costs	(17,454)	(3,013)	(40)
Repayments of capital lease obligations	(1,715)	(1,692)	(1,978)
Dividends paid to stockholders	(21,293)	(12,080)	(34,073)
Repurchase of common stock	(201,994)	(26,070)	(23,912)
Proceeds from exercise of stock options	6,858	5,172	8,786
Payments to satisfy minimum tax withholding	(1,481)	(927)	(1,654)
Issuance of common stock under employee stock purchase plan	3,615	2,854	2,549
Payments for contingent consideration arrangements	0	(537)	(5,748)
Distributions to noncontrolling interests	(4,750)	(1,300)	(1,600)
Excess tax benefits from share-based compensation	8,264	4,624	7,083
Net cash (used in) provided by financing activities	(229,950)	167,031	(50,587)
Effect of exchange rate changes on cash and cash equivalents	(2,796)	832	2,706
(Decrease) increase in cash and cash equivalents	(7,757)	(165,490)	93,981
Cash and cash equivalents at beginning of year	439,813	605,303	511,322
Cash and cash equivalents at end of period	$ 432,056	$ 439,813	$ 605,303