Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Retained Earnings
Balance (in shares) at May. 31, 2013		23,996
Balance at May. 31, 2013	$ 228,549	$ 37,724	$ 190,825
Issuance of shares under equity plan, net of shares withheld for employee taxes		12
Excess tax benefit for share-based compensation	183	$ 183
Non-cash stock compensation expense	1,356	$ 1,356
Dividends declared	(19,527)		(19,527)
Minimum tax withholdings on share-based compensation	(11)
Net income	20,408		20,408
Balance (in shares) at May. 31, 2014		24,008
Balance at May. 31, 2014	230,958	$ 39,252	191,706
Issuance of shares under equity plan, net of shares withheld for employee taxes		100
Excess tax benefit for share-based compensation	358	$ 358
Non-cash stock compensation expense	1,292	1,292
Dividends declared	(19,600)		(19,600)
Minimum tax withholdings on share-based compensation	(462)	$ (462)
Net income	15,432		15,432
Balance (in shares) at May. 31, 2015		24,108
Balance at May. 31, 2015	227,978	$ 40,440	187,538
Issuance of shares under equity plan, net of shares withheld for employee taxes		88
Excess tax shortfall for share-based compensation	(30)	$ (30)
Non-cash stock compensation expense	1,371	1,371
Dividends declared	(12,306)		(12,306)
Minimum tax withholdings on share-based compensation	(298)	$ (298)
Net income	4,784		4,784
Balance (in shares) at May. 31, 2016		24,196
Balance at May. 31, 2016	$ 221,499	$ 41,483	$ 180,016