Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2013

Summary of Activity in Corporation's Active Stock Plans

A combined summary of activity in the Corporation’s active stock plans is presented in the following table.

					Non-Vested Stock Awards/Stock Units Outstanding				Stock Options Outstanding
	Shares Available for Grant		Director Deferred Stock Units Outstanding		Number of Shares		Weighted- Average Grant-Date Fair Value		Number of Shares			Weighted- Average Exercise Price
Balance, January 1, 2013		1,157,413		27,724		188,560	$	51.67		5,513,516		$	51.94
Granted		—		—		—		—		—			—
Stock options exercised		—		—		—		—		(395,425	)		51.71
Stock awards vested		—		—		—		—
Forfeited		12,000		—		—		—		(12,000	)		51.78
Cancelled/expired		—		—		—		—		—
Balance, March 31, 2013		1,169,413		27,724		188,560	$	51.67		5,106,091		$	51.96

Shares Issued in Connection with Stock Compensation Awards

Shares issued in connection with stock compensation awards are issued from available treasury shares. If no treasury shares are available, new shares are issued from available authorized shares. Shares issued in connection with stock compensation awards along with other related information were as follows:

	Three Months Ended March 31,
	2013		2012
New shares issued from available authorized shares		153,275		101,160
Issued from available treasury stock		242,150		7,640
Total		395,425		108,800
Proceeds from stock option exercises	$	20,446	$	5,542

Stock-Based Compensation Expense

Stock-based compensation expense is recognized ratably over the requisite service period for all awards. Stock-based compensation expense was as follows:

	Three Months Ended March 31,
	2013		2012
Stock options	$	1,998	$	2,201
Non-vested stock awards/stock units		344		354
Total	$	2,342	$	2,555

Unrecognized Stock-Based Compensation Expense

Unrecognized stock-based compensation expense at March 31, 2013 was as follows:

Stock options	$	15,543
Non-vested stock awards/stock units		2,589
Total	$	18,132