Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			1,581,335	2,103,021
Earnings Per Share, Basic [Abstract]
Net income	$ 6,016	$ 1,375	$ 9,401	$ 3,726
Weighted Average Number of Shares Outstanding, Basic	34,450,000	33,390,000	34,177,000	33,377,000
Net income per share-basic	$ 0.17	$ 0.04	$ 0.28	$ 0.11
Earnings Per Share, Diluted [Abstract]
Weighted Average Number of Shares Outstanding, Basic	34,450,000	33,390,000	34,177,000	33,377,000
Dilutive Effect of Employee Stock Plans	$ 924	$ 926	$ 922	$ 952
Weighted Average Number of Shares Outstanding, Diluted	35,374,000	34,316,000	35,099,000	34,329,000
Net income per share - diluted	$ 0.17	$ 0.04	$ 0.27	$ 0.11