Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity balances, as adjusted	$ 315,566	$ 279	$ 127,058	$ 223,157	$ (26,907)	$ (6,845)	$ (1,176)
Retrospective adjustment upon adoption of ASU 2016-09	0		100	(100)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2016	315,566	279	126,958	223,257	(26,907)	(6,845)	(1,176)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,342			9,342			0
Other comprehensive income (loss)	(279)					(279)
Treasury shares sold to Employee Stock Purchase Plan	83		38		45
Exercise of stock options	46		(25)		71
Issuance of deferred shares	0		(4,259)		4,259
Other treasury share purchases	(1,878)				(1,878)
Stock-based compensation expense	1,652		1,652
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2016	324,532	279	124,464	232,499	(24,410)	(7,124)	(1,176)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2017	321,809	279	128,419	222,974	(22,539)	(7,324)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,824			3,824			0
Other comprehensive income (loss)	1,107					1,107
Treasury shares sold to Employee Stock Purchase Plan	66		(96)		162
Issuance of deferred shares	0		(2,883)		2,883
Other treasury share purchases	(454)				(454)
Stock-based compensation expense	2,086		2,086
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2017	$ 328,438	$ 279	$ 127,526	$ 226,798	$ (19,948)	$ (6,217)	$ 0