Condensed Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2012	$ 211,097	$ 279	$ 116,693	$ 117,419	$ (24,065)	$ 771	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	10,120			10,120			0
Other Comprehensive Income (Loss), Net of Tax	315					315
Exercise of stock options (31,800 and 16,600 shares for three month period ended September 30, 2013 and 2012, respectively)	106		(89)		195
Tax effect of exercised stock options and vesting of deferred shares	(27)		(27)
Issuance of deferred shares (644 and 106,394 shares for three month period ended September 30, 2013 and 2012, respectively)	0		(1,347)		1,347
Treasury shares sold to Employee Stock Purchase Plan (1,127 and 686 shares for three month period ended September 30, 2013 and 2012, respectively)	22		17		5
Other treasury share purchases (237 and 33,454 shares for three month period ended September 30, 2013 and 2012, respectively)	(1,065)				(1,065)
Stock-based compensation expense	1,812		1,812
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2012	222,380	279	117,059	127,539	(23,583)	1,086	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2013	238,162	279	118,190	141,427	(21,961)	227	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,863			16,858			5
Other Comprehensive Income (Loss), Net of Tax	(175)					(175)
Noncontrolling interest of consolidated joint venture	700						700
Exercise of stock options (31,800 and 16,600 shares for three month period ended September 30, 2013 and 2012, respectively)	602		(376)		978
Tax effect of exercised stock options and vesting of deferred shares	1,075		1,075
Issuance of deferred shares (644 and 106,394 shares for three month period ended September 30, 2013 and 2012, respectively)	0		(4,361)		4,361
Treasury shares sold to Employee Stock Purchase Plan (1,127 and 686 shares for three month period ended September 30, 2013 and 2012, respectively)	38		0		38
Other treasury share purchases (237 and 33,454 shares for three month period ended September 30, 2013 and 2012, respectively)	(1,638)				(1,638)
Stock-based compensation expense	2,515		2,515
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2013	$ 258,142	$ 279	$ 117,043	$ 158,285	$ (18,222)	$ 52	$ 705