Restatement of the Consolidated Financial Statements - Effects of Restatements on Consolidated Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	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, 2010	Dec. 31, 2009
Current assets:
Cash and cash equivalents	$ 31,055				$ 33,207				$ 13,561	$ 13,328
Restricted cash	21,314				45,476
Trade accounts receivable, less allowances of $13,543 and $9,341 at December 31, 2012 and 2011, respectively	107,312				99,888
Inventories	83,373				81,528
Deferred income taxes	33,450				36,313
Escrow receivable					41,537
Prepaid expenses and other current assets	34,079				21,999
Assets held for sale					171,185
Total current assets	310,583				531,133
Property, plant and equipment, net	53,835				46,137
Patents and other intangible assets, net	7,290				8,846
Goodwill	74,388				73,094				73,598
Deferred income taxes	18,881				16,741
Other long-term assets	7,920				9,429
Total assets	472,897	539,566	530,395	694,106	685,380	639,868	632,860	618,938
Current liabilities:
Bank borrowings	16				1,318
Current portion of long-term debt					17,500
Trade accounts payable	22,575				18,231
Accrued charges related to U.S. Government resolutions					83,138
Other current liabilities	39,594				40,836
Liabilities held for sale					22,676
Total current liabilities	62,185				183,699
Long-term debt	20,000				191,195
Deferred income taxes	11,456				9,778
Other long-term liabilities	11,424				8,634
Total liabilities	105,065	193,599	205,196	381,734	393,306	347,777	352,884	354,949
Contingencies (Note 17)
Shareholders' equity
Common shares $0.10 par value; 50,000,000 shares authorized; 19,339,329 issued and outstanding as of December 31, 2012 and $0.10 par value; 50,000,000 shares authorized; 18,465,444 issued and outstanding as of December 31, 2011	1,934				1,846
Additional paid-in capital	246,306				214,505
Retained earnings	114,847				72,009
Accumulated other comprehensive income	4,745				3,714
Total shareholders' equity	367,832	345,967	325,199	312,372	292,074	292,091	279,976	263,989
Total liabilities and shareholders' equity	472,897	539,566	530,395	694,106	685,380	639,868	632,860	618,938
Previously Reported [Member]
Current assets:
Cash and cash equivalents	31,055				33,207
Restricted cash	21,314				45,476
Trade accounts receivable, less allowances of $13,543 and $9,341 at December 31, 2012 and 2011, respectively	150,316				132,828
Inventories	88,744				82,969
Deferred income taxes	16,959				16,349
Escrow receivable					41,537
Prepaid expenses and other current assets	32,056				26,069
Assets held for sale					171,185
Total current assets	340,444				549,620
Property, plant and equipment, net	51,362				43,368
Patents and other intangible assets, net	6,880				8,236
Goodwill	74,388				73,094
Deferred income taxes	19,904				18,584
Other long-term assets	11,303				11,570
Total assets	504,281	565,073	553,320	707,586	704,472	656,073	647,026	631,284
Current liabilities:
Bank borrowings	16				1,318
Current portion of long-term debt					17,500
Trade accounts payable	21,812				16,488
Accrued charges related to U.S. Government resolutions					82,500
Other current liabilities	46,969				45,327
Liabilities held for sale					22,676
Total current liabilities	68,797				185,809
Long-term debt	20,000				191,195
Deferred income taxes	11,456				9,778
Other long-term liabilities	4,930				2,519
Total liabilities	105,183	187,463	199,104	369,178	389,301	345,130	349,116	354,201
Contingencies (Note 17)
Shareholders' equity
Common shares $0.10 par value; 50,000,000 shares authorized; 19,339,329 issued and outstanding as of December 31, 2012 and $0.10 par value; 50,000,000 shares authorized; 18,465,444 issued and outstanding as of December 31, 2011	1,934				1,846
Additional paid-in capital	246,111				214,310
Retained earnings	148,549				97,254
Accumulated other comprehensive income	2,504				1,761
Total shareholders' equity	399,098	377,610	354,216	338,408	315,171	310,943	297,910	277,083
Total liabilities and shareholders' equity	504,281	565,073	553,320	707,586	704,472	656,073	647,026	631,284
Adjustments [Member]
Current assets:
Trade accounts receivable, less allowances of $13,543 and $9,341 at December 31, 2012 and 2011, respectively	(43,004)				(32,940)
Inventories	(5,371)				(1,441)
Deferred income taxes	16,491				19,964
Prepaid expenses and other current assets	2,023				(4,070)
Total current assets	(29,861)				(18,487)
Property, plant and equipment, net	2,473				2,769
Patents and other intangible assets, net	410				610
Deferred income taxes	(1,023)				(1,843)
Other long-term assets	(3,383)				(2,141)
Total assets	(31,384)	(25,507)	(22,925)	(13,480)	(19,092)	(16,205)	(14,166)	(12,346)
Current liabilities:
Trade accounts payable	763				1,743
Accrued charges related to U.S. Government resolutions					638
Other current liabilities	(7,375)				(4,491)
Total current liabilities	(6,612)				(2,110)
Other long-term liabilities	6,494				6,115
Total liabilities	(118)	6,136	6,092	12,556	4,005	2,647	3,768	748
Contingencies (Note 17)
Shareholders' equity
Additional paid-in capital	195				195
Retained earnings	(33,702)				(25,245)
Accumulated other comprehensive income	2,241				1,953
Total shareholders' equity	(31,266)	(31,643)	(29,017)	(26,036)	(23,097)	(18,852)	(17,934)	(13,094)
Total liabilities and shareholders' equity	$ (31,384)	$ (25,507)	$ (22,925)	$ (13,480)	$ (19,092)	$ (16,205)	$ (14,166)	$ (12,346)