Basis of Presentation (Tables)

3 Months Ended

Mar. 31, 2013

Accounting Policies [Abstract]

Stock Options Outstanding

The following table provides information about our stock options outstanding for the three months ended March 31, 2013 and 2012:

	March 31, 2013					March 31, 2012
	Shares			Weighted- Average Exercise Price		Shares			Weighted- Average Exercise Price
Stock Options:
Outstanding at beginning of period		335,730		$	42.14		416,886		$	43.52
Granted		122,357			47.50		32,830			40.89
Exercised		(22,283	)		31.36		(1,815	)		24.94
Outstanding at end of period		435,804			44.19		447,901			43.41
Exercisable at end of period		197,943		$	44.52		337,764		$	45.00
Weighted-average fair value of awards granted	$	10.32				$	12.38

Schedule of Vesting Information Stock Options Outstanding

The following table provides vesting information about our stock options outstanding for the three months ended March 31, 2013 and 2012:

	March 31, 2013					March 31, 2012
	Shares			Weighted- Average Exercise Price		Shares			Weighted- Average Exercise Price
Stock Options:
Unvested at beginning of period		157,298		$	38.57		112,258		$	36.08
Granted		122,357			47.50		32,830			40.89
Vested		(41,794	)		34.30		(34,951	)		32.89
Unvested at end of period		237,861		$	43.92		110,137		$	38.53