Share-Based Payment Arrangements	3 Months Ended
Mar. 31, 2012
Share-Based Payment Arrangements [Abstract]
Share-Based Payment Arrangements	10. Share-Based Payment Arrangements Share-based compensation expense, net of tax, of $2.0 million and $2.3 million was charged against income during the first quarter of 2012 and 2011, respectively. During the first quarter of 2012, the Corporation had 1,088,428 stock options exercised at a weighted average exercise price of $32.84 per share and had 4,313 stock options forfeited or expired.

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

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+ Details