Note 6 - Acquisitions (Tables)

3 Months Ended

Jul. 31, 2014

Business Combinations [Abstract]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]

Assets acquired:
Inventories	$	2,208
Property and equipment		22,075
Total assets		24,283
Liabilities assumed:
Accrued expenses		34
Total liabilities		34
Net tangible assets acquired, net of cash		24,249
Goodwill and other intangible assets		6,525
Total consideration paid, net of cash acquired	$	30,774

Business Acquisition, Pro Forma Information [Table Text Block]

	Three months ended July 31,
	2014		2013
Total revenues	$	2,291,186		2,210,709
Net earnings		52,290		57,708
Earnings per common share:
Basic	$	1.35		1.50
Diluted	$	1.34		1.49