Pension plan (Tables)

9 Months Ended

Oct. 31, 2012

Pension plan [Abstract]

Market value of plan assets [Table Text Block]

Level 1 market value of plan assets	October 31, 2012		January 31, 2012
Equity securities		$3,175		$3,018
U.S. bond market	2,141		1,968
High-quality inflation-indexed bonds issued by the U.S. Treasury and government agencies as well as domestic corporations	281		268
Real estate	118		110
Subtotal	5,715		5,364
Level 2 significant other observable inputs
Money market fund	252		138
Total		$5,967		$5,502

Components of net periodic benefit costs[Table Text Block]

	Three Months Ended October 31,						Nine Months Ended October 31,
Components of net periodic benefit costs	2012			2011			2012			2011
Service cost		$43			$31			$128			$94
Interest cost	75			79			224			235
Expected return on plan assets	(111		)	(101		)	(333		)	(304		)
Amortization of prior service cost	12			31			37			95
Recognized actuarial loss	43			16			130			47
Net periodic benefit costs		$62			$56			$186			$167