CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2013	$ 936,000	$ 296,517,000	$ 250,000,000	$ (45,014,000)	$ 502,439,000
Balance (in shares) at Dec. 31, 2013	93,826,453			6,526,305
Increase (Decrease) in Shareholders' Equity
Net income and comprehensive income			16,341,000		16,341,000
Stock-based compensation cost		9,095,000			9,095,000
Exercise of stock options	3,000	3,276,000			3,279,000
Exercise of stock options (in shares)	352,057
Vesting of restricted stock awards and units, net of shares withheld for employee tax	1,000	(1,129,000)			(1,128,000)
Vesting of restricted stock awards and units, net of shares withheld for employee tax (in shares)	110,138
Deferred tax reversal for unexercised stock options		(395,000)			(395,000)
Excess tax benefit from exercise of stock options		870,000			870,000
Balance at Sep. 30, 2014	$ 940,000	$ 308,234,000	$ 266,341,000	$ (45,014,000)	$ 530,501,000
Balance (in shares) at Sep. 30, 2014	94,288,648			6,526,305