Restatement of Consolidated Financial Statements - Schedule of Restatement Adjustments and Impact on Previously Reported Consolidated Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 01, 2011	Dec. 31, 2010
Current assets
Cash and cash equivalents	$ 153,606	$ 182,238	$ 162,111		$ 172,172
Restricted cash	4	133	6,830
Accounts receivable, net	78,898	105,983	102,622
Inventories, net	74,698	82,384	62,683
Other receivables	6,011	1,560	509
Prepaid expenses	9,194	7,884	6,032
Current deferred income tax assets	1,348	1,788	2,076
Other current assets	10,403	10,624	12,471
Total current assets	334,162	392,594	355,334
Property, plant and equipment, net	254,297	237,392	182,663
Intangible assets, net	3,111	15,260	16,787
Long-term prepaid expenses	16,405	18,048	4,790
Deferred income tax assets	896	2,586	4,770
Other non-current assets	16,319	14,866	15,002
Total assets	625,190	680,746	579,346
Current liabilities
Accounts payable	75,059	79,365	77,880
Other accounts payable	15,670	16,759	13,452
Accrued expenses	65,494	47,375	35,469
Current portion of capital lease obligation			2,852
Derivative liabilities		944	9,757
Other current liabilities	5,872	9,544	3,893
Total current liabilities	162,095	153,987	143,303
Long-term borrowings, net	223,923	201,653	201,389
Accrued severance benefits, net	134,172	114,858	92,432
Other non-current liabilities	23,459	18,719	8,050
Total liabilities	543,649	489,217	445,174
Commitments and contingencies (Note 20)
Stockholders' equity
Common stock	406	396	394
Additional paid-in capital	116,222	102,409	99,060
Retained earnings	105,889	170,092	60,054	71,355
Treasury stock	(90,918)	(39,918)	(11,793)
Accumulated other comprehensive loss	(50,058)	(41,450)	(13,543)		(5,275)
Total stockholders' equity	81,541	191,529	134,172		161,222
Total liabilities and stockholders' equity	625,190	680,746	579,346
As Previously Reported [Member]
Current assets
Cash and cash equivalents		182,238	162,111		172,172
Restricted cash		133	6,830
Accounts receivable, net		143,331	125,922
Inventories, net		89,363	62,836
Other receivables		1,429	256
Prepaid expenses		7,884	6,032
Current deferred income tax assets		22,768	3,406
Other current assets		9,680	12,503
Total current assets		456,826	379,896
Property, plant and equipment, net		238,256	182,663
Intangible assets, net		15,260	16,787
Long-term prepaid expenses		18,048	4,790
Deferred income tax assets		46,710	3,537
Other non-current assets		14,866	15,002
Total assets		789,966	602,675
Current liabilities
Accounts payable		79,236	77,848
Other accounts payable		15,600	13,452
Accrued expenses		43,486	31,723
Current portion of capital lease obligation			2,852
Derivative liabilities			9,757
Other current liabilities		9,973	2,007
Total current liabilities		148,295	137,639
Long-term borrowings, net		201,653	201,389
Accrued severance benefits, net		112,446	90,755
Other non-current liabilities		17,263	6,222
Total liabilities		479,657	436,005
Commitments and contingencies (Note 20)
Stockholders' equity
Common stock		396	394
Additional paid-in capital		101,885	98,929
Retained earnings		287,251	93,950	72,157
Treasury stock		(39,918)	(11,793)
Accumulated other comprehensive loss		(39,305)	(14,810)
Total stockholders' equity		310,309	166,670		162,851
Total liabilities and stockholders' equity		789,966	602,675
Adjustments [Member]
Current assets
Accounts receivable, net		(37,348)	(23,300)
Inventories, net		(6,979)	(153)
Other receivables		131	253
Current deferred income tax assets		(20,980)	(1,330)
Other current assets		944	(32)
Total current assets		(64,232)	(24,562)
Property, plant and equipment, net		(864)
Deferred income tax assets		(44,124)	1,233
Total assets		(109,220)	(23,329)
Current liabilities
Accounts payable		129	32
Other accounts payable		1,159
Accrued expenses		3,889	3,746
Derivative liabilities		944
Other current liabilities		(429)	1,886
Total current liabilities		5,692	5,664
Accrued severance benefits, net		2,412	1,677
Other non-current liabilities		1,456	1,828
Total liabilities		9,560	9,169
Commitments and contingencies (Note 20)
Stockholders' equity
Additional paid-in capital		524	131
Retained earnings		(117,159)	(33,896)	(802)
Accumulated other comprehensive loss		(2,145)	1,267
Total stockholders' equity		(118,780)	(32,498)		(1,629)
Total liabilities and stockholders' equity		(109,220)	(23,329)
Adjustments [Member] | Revenue Recognition [Member]
Current assets
Accounts receivable, net		(37,217)	(23,055)
Inventories, net		11,787	10,221
Total current assets		(25,430)	(12,834)
Total assets		(25,430)	(12,834)
Current liabilities
Other current liabilities		(636)	1,918
Total current liabilities		(636)	1,918
Total liabilities		(636)	1,918
Commitments and contingencies (Note 20)
Stockholders' equity
Retained earnings		(24,061)	(15,583)
Accumulated other comprehensive loss		(733)	831
Total stockholders' equity		(24,794)	(14,752)
Total liabilities and stockholders' equity		(25,430)	(12,834)
Adjustments [Member] | Inventory Reserves [Member]
Current assets
Inventories, net		(18,917)	(10,049)
Total current assets		(18,917)	(10,049)
Total assets		(18,917)	(10,049)
Current liabilities
Commitments and contingencies (Note 20)
Stockholders' equity
Retained earnings		(18,253)	(10,133)
Accumulated other comprehensive loss		(664)	84
Total stockholders' equity		(18,917)	(10,049)
Total liabilities and stockholders' equity		(18,917)	(10,049)
Adjustments [Member] | Understated Employee Benefits [Member]
Current liabilities
Accrued severance benefits, net		2,412	1,677
Other non-current liabilities		2,615	1,828
Total liabilities		5,027	3,505
Commitments and contingencies (Note 20)
Stockholders' equity
Retained earnings		(4,740)	(3,830)	(1,358)
Accumulated other comprehensive loss		(287)	325
Total stockholders' equity		(5,027)	(3,505)
Adjustments [Member] | Settlement Obligations [Member]
Current liabilities
Accrued expenses		1,322	2,100
Total current liabilities		1,322	2,100
Total liabilities		1,322	2,100
Commitments and contingencies (Note 20)
Stockholders' equity
Retained earnings		(1,307)	(2,116)
Accumulated other comprehensive loss		(15)	16
Total stockholders' equity		(1,322)	(2,100)
Adjustments [Member] | Tax Matters [Member]
Current assets
Current deferred income tax assets		(20,980)	(1,330)
Other current assets			(32)
Total current assets		(20,980)	(1,362)
Deferred income tax assets		(44,124)	1,233
Total assets		(65,104)	(129)
Current liabilities
Accrued expenses		2,111	1,216
Other current liabilities		207	(32)
Total current liabilities		2,318	1,184
Total liabilities		2,318	1,184
Commitments and contingencies (Note 20)
Stockholders' equity
Retained earnings		(66,993)	(1,319)
Accumulated other comprehensive loss		(429)	6
Total stockholders' equity		(67,422)	(1,313)
Total liabilities and stockholders' equity		(65,104)	(129)
Adjustments [Member] | Account Classification [Member]
Current assets
Accounts receivable, net		(131)
Other receivables		131
Current liabilities
Commitments and contingencies (Note 20)
Adjustments [Member] | Other Adjustments [Member]
Current assets
Inventories, net		151	(325)
Other receivables			8
Other current assets		944
Total current assets		1,095	(317)
Property, plant and equipment, net		(864)
Total assets		231	(317)
Current liabilities
Accounts payable		129	32
Other accounts payable		1,159
Accrued expenses		456	430
Derivative liabilities		944
Total current liabilities		2,688	462
Other non-current liabilities		(1,159)
Total liabilities		1,529	462
Commitments and contingencies (Note 20)
Stockholders' equity
Additional paid-in capital		524	131
Retained earnings		(1,805)	(915)
Accumulated other comprehensive loss		(17)	5
Total stockholders' equity		(1,298)	(779)
Total liabilities and stockholders' equity		231	(317)
Adjustments [Member] | Account Reclassification [Member]
Current assets
Accounts receivable, net			(245)
Other receivables			245
Current liabilities
Commitments and contingencies (Note 20)