Geographic Areas (Schedule Of Segment Reporting) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Products									$ 610,218	$ 511,650	$ 486,050
Services									122,813	89,692	80,201
Intercompany									70,836	79,996	55,424
Eliminations									(70,836)	(79,996)	(55,424)
Total revenues	188,477	190,860	176,570	177,124	171,646	155,035	136,994	137,667	733,031	601,342	566,251
Total long-lived assets eliminations	(2,959)				(2,809)				(2,959)	(2,809)	(2,549)
Income (loss) before income taxes									162,122	130,004	138,903
Total long-lived assets	307,059				286,556				307,059	286,556	260,302
Total assets eliminations	(32,982)				(19,243)				(32,982)	(19,243)	(22,715)
Total assets	1,231,447				1,085,858				1,231,447	1,085,858	948,551
Western Hemisphere [Member]
Segment Reporting Information [Line Items]
Products									298,853	265,029	273,747
Services									68,938	37,531	36,587
Intercompany									65,803	73,290	50,447
Total revenues									433,594	375,850	360,781
Income (loss) before income taxes									76,771	66,782	63,987
Total long-lived assets	215,340				196,380				215,340	196,380	179,392
Total assets	727,242				666,915				727,242	666,915	593,648
Eastern Hemisphere [Member]
Segment Reporting Information [Line Items]
Products									196,328	164,135	130,764
Services									37,307	33,320	30,435
Intercompany									4,065	3,680	2,489
Total revenues									237,700	201,135	163,688
Income (loss) before income taxes									44,904	41,453	29,773
Total long-lived assets	36,194				34,927				36,194	34,927	36,924
Total assets	275,868				229,043				275,868	229,043	185,903
Asia-Pacific [Member]
Segment Reporting Information [Line Items]
Products									115,037	82,486	81,539
Services									16,568	18,841	13,179
Intercompany									968	3,026	2,488
Total revenues									132,573	104,353	97,206
Income (loss) before income taxes									33,478	22,891	35,071
Total long-lived assets	58,484				58,058				58,484	58,058	46,535
Total assets	261,319				209,143				261,319	209,143	191,715
Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before income taxes									$ 6,969	$ (1,122)	$ 10,072