Balance Sheet Details (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Accounts receivable:
Accounts receivable	$ 106,345	$ 94,549
Allowance for doubtful accounts	6,234	5,846
Inventories:
Finished goods	163,247	144,945
Work in process	1,687	1,615
Raw materials	4,790	4,558
Repair parts	11,058	10,550
Operating supplies	1,318	1,453
Total inventories, less loss provisions of $4,577 and $4,913	182,100	163,121
Inventory loss provisions	4,577	4,913
Prepaid and other current assets:
Value added tax	13,254	6,697
Prepaid expenses	10,674	8,396
Deferred income taxes	5,840	5,840
Prepaid income taxes	4,970	3,511
Derivative asset	182	394
Total prepaid and other current assets	34,920	24,838
Other assets:
Deposits	1,092	919
Finance fees — net of amortization	7,484	10,472
Other assets	2,392	2,143
Total other assets	10,968	13,534
Accrued liabilities:
Accrued incentives	24,156	17,830
Workers compensation	6,873	7,108
Medical liabilities	3,109	3,433
Interest	3,871	3,331
Commissions payable	1,072	1,067
Withholdings and other non-income tax accruals	2,134	1,929
Other accrued liabilities	7,200	6,720
Total accrued liabilities	48,415	41,418
Other long-term liabilities:
Deferred liability	7,237	7,424
Derivative liability	76	2,073
Other long-term liabilities	4,426	4,277
Total other long-term liabilities	11,739	13,774
Trade receivables
Accounts receivable:
Accounts receivable	104,114	87,499
Other receivables [Member]
Accounts receivable:
Accounts receivable	$ 2,231	$ 7,050