Shareholders' Equity (Details) $ in Thousands	1 Months Ended			12 Months Ended
	Aug. 31, 2017 USD ($)	Aug. 31, 2016 USD ($)	Aug. 31, 2015 USD ($)	Jul. 31, 2017 USD ($) shares	Jul. 31, 2016 USD ($) shares	Jul. 31, 2015 USD ($) Installments shares	Aug. 31, 2010 shares
Cash Dividends [Abstract]
Cash dividends declared				$ 1,719	$ 1,895	$ 2,067
Dividends paid		$ 900	$ 1,000	1,700	2,100	2,100
Schedule of Equity Method Investments [Line Items]
Purchase of noncontrolling interest				0	0	50
Other Comprehensive Loss, Net of Tax [Abstract]
Unrealized net foreign currency translation losses				(2,033)	(2,176)
Unrealized net investment gains on available for sale investments				15	33
Total accumulated other comprehensive loss				(2,018)	(2,143)
Subsequent Event [Member]
Cash Dividends [Abstract]
Dividends paid	$ 900
Noncontrolling Interest [Member]
Cash Dividends [Abstract]
Cash dividends declared				$ 0	$ 0	$ 0
Noncontrolling Interest [Member] | Gustavson [Member]
Schedule of Equity Method Investments [Line Items]
Interest purchased						7.20%
Purchase of noncontrolling interest						$ 300
Purchase of noncontrolling interest, 1st installment						100
Purchase of noncontrolling interest, three annual installments						$ 200
Number of annual installments | Installments						3
Interest on promissory notes						6.00%
Increase in indirect ownership						83.60%
Class A [Member]
Class A and Class B common stock [Abstract]
Percentage equity holders entitled to elect Board of Directors				25.00%
Minimum percentage of the number of outstanding Class A shares to combined classes of shares				10.00%
Voting power of Class A common share holders to the Class B common share holders				0.1
Number of Class B shares to be converted into Class A shares (in shares) | shares				1
Stock Repurchase [Abstract]
Number of shares authorized to be repurchased (in shares) | shares				122,918			200,000
Remaining number of shares authorized to be repurchased (in shares) | shares				77,082
Number of share acquired (in shares) | shares				0	0	0