Borrowings - Additional Information (Detail)	9 Months Ended		0 Months Ended									9 Months Ended			0 Months Ended	3 Months Ended		9 Months Ended					9 Months Ended				9 Months Ended		0 Months Ended		9 Months Ended	1 Months Ended		9 Months Ended											9 Months Ended	0 Months Ended
	Sep. 30, 2012 USD ($)	Sep. 30, 2012 RUB	Dec. 02, 2009 9.125% Senior Secured Notes Due 2016 [Member] USD ($)	Dec. 02, 2009 8.875% Senior Secured Notes Due 2016 [Member] USD ($)	Dec. 02, 2009 8.875% Senior Secured Notes Due 2016 [Member] EUR (€)	Dec. 09, 2010 8.875% Senior Secured Notes Due 2016 [Member] Additional Debt [Member] USD ($)	Dec. 09, 2010 8.875% Senior Secured Notes Due 2016 [Member] Additional Debt [Member] EUR (€)	Sep. 30, 2012 Raiffeisen Bank [Member] USD ($)	Sep. 30, 2012 Raiffeisen Bank [Member] EUR (€)	Sep. 30, 2012 Zenit Bank, Alfa Bank And Raiffeisen Bank [Member] USD ($)	Jun. 30, 2012 Zenit Bank, Alfa Bank And Raiffeisen Bank [Member] EUR (€)	Sep. 30, 2012 Alfa Bank [Member] Tranches	Sep. 30, 2012 Senior Notes due March 18, 2013 (New Debt) [Member] USD ($)	Dec. 31, 2011 Senior Notes due March 18, 2013 (New Debt) [Member] USD ($)	Mar. 07, 2008 Convertible Senior Notes Due 2013 [Member] USD ($)	Sep. 30, 2012 Convertible Senior Notes Due 2013 [Member] USD ($)	Sep. 30, 2011 Convertible Senior Notes Due 2013 [Member] USD ($)	Sep. 30, 2012 Convertible Senior Notes Due 2013 [Member] USD ($)	Sep. 30, 2011 Convertible Senior Notes Due 2013 [Member] USD ($)	Dec. 31, 2011 Convertible Senior Notes Due 2013 [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] Unicredit And JSC Grand Invest Bank [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] Unicredit And JSC Grand Invest Bank [Member] RUB	Sep. 30, 2012 Loan Agreement [Member] Unicredit [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] Unicredit [Member] RUB	Sep. 30, 2011 Loan Agreement [Member] Unicredit [Member] USD ($)	Sep. 30, 2011 Loan Agreement [Member] Unicredit [Member] RUB	Sep. 30, 2012 Loan Agreement [Member] JSC Grand Invest Bank [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] JSC Grand Invest Bank [Member] RUB	Jul. 06, 2010 Loan Agreement [Member] Raiffeisen Bank [Member] USD ($) Tranches	Jul. 06, 2010 Loan Agreement [Member] Raiffeisen Bank [Member] EUR (€) Tranches	Sep. 30, 2012 Loan Agreement [Member] Raiffeisen Bank [Member]	Jul. 22, 2008 Loan Agreement [Member] Alfa Bank [Member] USD ($)	Jul. 22, 2008 Loan Agreement [Member] Alfa Bank [Member] EUR (€)	Sep. 30, 2012 Loan Agreement [Member] Alfa Bank [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] Alfa Bank [Member] EUR (€)	Sep. 30, 2012 Loan Agreement [Member] Alfa Bank [Member] Minimum [Member]	Sep. 30, 2012 Loan Agreement [Member] Alfa Bank [Member] Maximum [Member]	Sep. 30, 2012 Loan Agreement [Member] MKB Bank [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] MKB Bank [Member] RUB	Sep. 30, 2012 Loan Agreement [Member] Outstanding Loan Balance [Member] USD ($)	Sep. 30, 2012 Loan Agreement [Member] Outstanding Loan Balance [Member] RUB	Sep. 30, 2012 Overdraft Agreement [Member] Sberbank [Member]	Feb. 06, 2012 Overdraft Agreement [Member] Sberbank [Member] USD ($)	Feb. 06, 2012 Overdraft Agreement [Member] Sberbank [Member] RUB	Sep. 30, 2012 Convertible Note [Member] USD ($) Tranches	Jan. 04, 2010 Senior Secured Notes Due 2016 [Member] USD ($)	Jan. 04, 2010 Senior Secured Notes Due 2016 [Member] EUR (€)	Sep. 30, 2012 Senior Secured Notes Due 2016 [Member] USD ($)	Dec. 31, 2011 Senior Secured Notes Due 2016 [Member] USD ($)
Line of Credit Facility [Line Items]
Outstanding liability								$ 7,100,000	€ 5,500,000	$ 29,100,000	€ 22,500,000										$ 76,600,000	2,371,400,000	$ 19,400,000	600,000,000			$ 6,800,000	211,400,000						$ 22,000,000	€ 17,000,000			$ 32,300,000	1,000,000,000	$ 18,100,000	560,000,000
Initiation date	July 6, 2012	July 6, 2012																					May 24, 2011	May 24, 2011			November 25, 2011	November 25, 2011			March 29, 2011			July 22, 2008	July 22, 2008			July 19, 2012	July 19, 2012	July 25, 2012	July 25, 2012	February 6, 2012
Maturity date	December 29, 2012	December 29, 2012																					November 25, 2012	November 25, 2012			November 23, 2012	November 23, 2012			June 6, 2012	October 18, 2014	October 18, 2014					February 25, 2013	February 25, 2013	December 31, 2012	December 31, 2012	February 5, 2013
Maximum borrowing capacity	16,200,000	500,000,000																											12,900,000	10,000,000		25,900,000	20,000,000										1,900,000	60,000,000
Loan agreement, number of tranches												7																	2	2															6
Date of tranches release, start date																															August 16, 2012			March 30, 2012	March 30, 2012
Date of tranches release, end date																															September 10, 2012			September 26, 2012	September 26, 2012
Repayable date																																				September 30, 2012	December 28, 2012
Amount of collateral on term loan																									23,300,000	720,000,000
Term loan facility utilized portion	5,600,000	173,400,000
Debt instrument issuance amount	70,000,000		380,000,000	491,900,000	380,000,000	64,700,000	50,000,000						70,000,000		310,000,000
Interest rate percentage on issued debt	3.00%	3.00%	9.125%	8.875%	8.875%	8.875%	8.875%						3.00%		3.00%
Year of maturity of debt															2013
Initial conversion rate shares															14.7113
Principal amount of initial conversion rate															1,000
Repurchased amount of convertible notes																																													52,100,000
Principal amount of convertible notes																																													50,200,000
Accrued interest																500,000		500,000		2,700,000																												28,000,000	7,000,000
Pre tax non-cash interest expense recognized in consolidated statement of operations																1,500,000	1,100,000	4,100,000	3,200,000
Annual pre-tax increase in non-cash interest expense																		400,000
Debt instrument maturity year			2016	2016	2016	2016	2016
Redemption of senior secured notes																																														317,700,000	245,400,000
Debt instrument maturity date													Mar. 18, 2013
Common stock to be purchased, shares													13,300,000
Common stock to be purchased, price per share													$ 5.25
Common stock price per share for interest payable on debt security													$ 3.44
Accrued interest													700,000
Unamortized debt discount													$ 18,700,000	$ 16,500,000