Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 164,947	$ 217,049	$ 369,873
Less: Income from discontinued operations			1,545
Less: Gain on disposal of discontinued operations			24,371
Income from continuing operations	164,947	217,049	343,957
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Depreciation	57,317	55,049	51,040
Amortization	93,370	90,465	55,641
Stock-based compensation	36,612	39,920	32,337
Provision for excess and obsolete inventory	16,592	26,849	11,601
Deferred taxes	(4,284)	5,556	(146,949)
Gain from the sale of an equity investment	(34,212)
Tax benefit related to stock options and restricted stock units	(2,596)	(8,358)
Non cash charge for the sale of inventories revalued at the date of acquisition		6,089	12,178
Retirement plans actuarial (gains) losses	(10,340)	23,320	13,564
Contingent consideration adjustment		(8,761)
Other	(407)	(2,250)	(794)
Changes in operating assets and liabilities, net of businesses sold and acquired:
Accounts receivable	(3,656)	(24,093)	66,367
Inventories	21,170	17,652	(615)
Prepayments and other assets	(49,572)	(2,995)	(21,509)
Accounts payable and other accrued expenses	15,103	(32,810)	(48,222)
Deferred revenue and customer advances	(28,877)	(14,627)	(68,359)
Retirement plan contributions	(5,540)	(4,778)	(11,851)
Accrued income taxes	1,648	19,804	(8,727)
Net cash provided by continuing operations	267,275	403,081	279,659
Net cash used for discontinued operations			(4,804)
Net cash provided by operating activities	267,275	403,081	274,855
Cash flows from investing activities:
Purchases of property, plant and equipment	(106,731)	(119,080)	(86,097)
Purchases of available-for-sale marketable securities	(1,168,621)	(748,229)	(685,823)
Acquisition of businesses, net of cash acquired	(14,999)		(537,489)
Proceeds from maturities of available-for-sale marketable securities	516,499	225,085	442,080
Proceeds from sales of available-for-sale marketable securities	458,120	38,284	746,810
Proceeds from the sale of an equity investment	34,212
(Purchases of ) proceeds from life insurance	(307)	1,451	(1,091)
Net cash used for continuing operations	(281,827)	(602,489)	(121,610)
Net cash provided by discontinued operations			39,062
Net cash used for investing activities	(281,827)	(602,489)	(82,548)
Cash flows from financing activities:
Issuance of common stock under stock option and stock purchase plans	17,596	18,477	17,385
Tax benefit related to stock options and restricted stock units	2,596	8,358
Payments of long-term debt	(2,534)	(2,533)	(2,518)
Payments of contingent consideration	(388)	(59,710)
Repurchase of common stock			(31,175)
Net cash provided by (used for) financing activities	17,270	(35,408)	(16,308)
Increase (decrease) in cash and cash equivalents	2,718	(234,816)	175,999
Cash and cash equivalents at beginning of year	338,920	573,736	397,737
Cash and cash equivalents at end of year	341,638	338,920	573,736
Cash paid during the year for:
Interest	8,590	8,602	8,645
Income taxes	$ 38,156	$ 8,084	$ 36,043