Commitment and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Jan. 31, 2013
Company's future principal contractual obligations
2014	$ 2,587
2015	2,842
2016	2,300
2017	2,188
2018	1,996
Thereafter	2,535
Total	14,448
Credit Facility:
Long-term Debt, Total	410,042	410,042
2014	18,403
2015	24,481
2016	24,481
2017	4,073
Total	71,438
2014	20,990
2015	27,323
2016	26,781
2017	416,303
2018	1,996
Thereafter	2,535
Total	495,928
2016 Tranche B term loans: due March 10, 2016, three-month LIBOR plus 4.00% with a 1.00% LIBOR floor [Member]
Credit Facility:
Long-term Debt, Total	117,399	117,399
2016 Extended term loans: due March 10, 2016, three-month LIBOR plus 4.00% [Member]
Credit Facility:
Long-term Debt, Total	191,101	191,101
Senior Subordinated Notes: due March 15, 2016, 10.375% [Member]
Credit Facility:
Long-term Debt, Total	101,542	101,542
Credit Facility [Member] | 2016 Tranche B term loans: due March 10, 2016, three-month LIBOR plus 4.00% with a 1.00% LIBOR floor [Member]
Credit Facility:
2017	117,399
Long-term Debt, Total	117,399
Credit Facility [Member] | 2016 Extended term loans: due March 10, 2016, three-month LIBOR plus 4.00% [Member]
Credit Facility:
2017	191,101
Long-term Debt, Total	191,101
Credit Facility [Member] | Senior Subordinated Notes: due March 15, 2016, 10.375% [Member]
Credit Facility:
2017	101,542
Long-term Debt, Total	$ 101,542