Capital Stock (Details Textual) (USD $)	12 Months Ended					1 Months Ended		5 Months Ended	12 Months Ended					3 Months Ended	12 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended		1 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	May 05, 2011	Jan. 27, 2011	Jun. 30, 2010	May 31, 2011 Common Stock Class A [Member]	Jan. 31, 2011 Common Stock Class A [Member]	May 31, 2009 Common Stock Class A [Member]	Jan. 31, 2012 Common Stock Class A [Member]	Jan. 31, 2011 Common Stock Class A [Member]	Jan. 31, 2010 Common Stock Class A [Member]	Jan. 31, 2012 Common Stock Class B [Member]	Jan. 31, 2011 Common Stock Class B [Member]	Mar. 14, 2012 Series A Preferred Stock [Member]	Jan. 31, 2012 Series A Preferred Stock [Member]	Jan. 31, 2011 Series A Preferred Stock [Member]	Mar. 09, 2010 Series A Preferred Stock [Member]	Mar. 04, 2010 Series A Preferred Stock [Member]	Jan. 31, 2011 Senior Notes due 2011 [Member]	Mar. 04, 2010 Senior Notes due 2011 [Member]	Jan. 31, 2011 Senior Notes due 2015 [Member]	Mar. 04, 2010 Senior Notes due 2015 [Member]	Jan. 31, 2011 Senior Notes 2017 [Member]	Mar. 04, 2010 Senior Notes 2017 [Member]	May 31, 2011 5.000% Convertible Senior Notes due 2016 [Member]	Jan. 31, 2011 5.000% Convertible Senior Notes due 2016 [Member]
Debt Instrument [Line Items]
Senior note exchanged for stock, value of senior note exchanged																			$ 51,176,000		$ 121,747,000		$ 5,826,000		$ 40,000,000	$ 110,000,000
Value of preferred stock exchanged for senior notes																				50,664,000		114,442,000		4,894,000
Class of Stock [Line Items]
Common Stock Voting Rights Percentage									25.00%			75.00%
Common stock voting right									one vote per share			Ten vote per share
Common stock, shares authorized					371,000,000		371,000,000		371,000,000	371,000,000		56,000,000	56,000,000
Share of Class A common stock issued in exchange of debt						3,444,293	9,774,039		3,444,000	9,774,000
Number of share in exchange of note for per conversion			71.8894	71.8894
Number of share increased in exchange of note for per conversion			86.1073	88.8549
Value of note for per conversion			1,000	1,000
Aggregate principal amount of notes exchanged										110,000,000
Aggregate number of shares exchanged										9,774,039
Class A common stock shares sold in public offering								52,325,000			52,325,000
Price per share							$ 0.333	$ 6.60	$ 0.333	$ 0.333		$ 0.333	$ 0.333
Shares issued as a result of the underwriters' exercise of their over-allotment option in full								6,825,000
Net proceeds after deductions								329,917,000
Series A preferred stock issued																		50,000,000
Series A preferred stock issued															4,399,998	4,399,998	4,400,000
Proceeds from Preferred Stock Issuance Net of Equity Hedge and Transaction Costs																26,900,000
Stock conversion description							Conversion rate increased from 71.8894 shares per $1,000 principal amount of notes to 88.8549 shares, which factors in lost interest to the holders among other inducements. Under the terms of the agreements, holders agreed to exchange $110,000,000 in aggregate principal amount of notes for a total of 9,774,039 shares of Class A common stock								Holder would receive approximately 3.3 shares of Class A common stock per $50 liquidation preference of Series A preferred stock
Initial conversion price of class A common stock															$ 15.12
Preferred stock conversion description															Daily Volume Weighted Average Price of its Class A common stock equals or exceeds 150% of the initial conversion price then in effect for at least 20 out of 30 consecutive trading days
Effective Conversion Price of Common Stock															$ 18.27
Undeclared Series A preferred stock dividends															1,925,000
Declared paid and unpaid cash dividends on preferred stock series A	$ 15,400,000	$ 11,807,000												$ 3,850,000	$ 15,400,000	$ 11,807,000
Preferred stock, shares authorized					20,000,000										6,400,000	6,400,000		6,400,000
Number of common shares in lieu of preferred stock liquidation									3.3
Preferred stock, liquidation preference															$ 50	$ 50
Number consecutive trading days															30 days
Number of initial conversion Days for determination of conversion price															20 days
Percentage initial conversion price															150.00%