Stock Based Compensation Expense (Details) (USD $)	3 Months Ended
Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Summary of Option activity
Incentive Stock Option Plans, Beginning balance	1,274,462	1,353,174	1,388,514
Weighted Average Price Per Share, Beginning balance	$ 6.94	$ 7.28	$ 7.44
Exercisable Weighted Average Price Per Share, Beginning balance	$ 6.27	$ 6.95	$ 7.26
Incentive Stock Option Plans, Options granted
Weighted Average Price Per Share, Option granted	$ 0.00	$ 0.00	$ 0.00
Incentive Stock Option Plans, Option exercised	(109,681)	(64,712)	(35,340)
Weighted Average Price Per Share, Option exercised	$ 14.75	$ 13.77	$ 13.37
Incentive Stock Option Plans, Option expired or forfeited		(14,000)
Weighted Average Price Per Share, Option expired or forfeited	$ 0.00	$ 7.50	$ 0.00
Incentive Stock Option Plans, Ending balance	1,164,781	1,274,462	1,353,174
Weighted Average Price Per Share, Ending balance	$ 6.20	$ 6.94	$ 7.28
Exercisable Weighted Average Price Per Share, Ending balance	$ 4.60	$ 6.27	$ 6.95

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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