Stock-Based Compensation (details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
LTIP Paragraph 1 [Abstract]
Common stock was authorized for grants under the LTIP		37,300
Weighted-average per share grant date fair value of unvested shares	$ 38.96	$ 38.96
Fair value pricing model LTIP		Monte-Carlo option pricing model
Stock price on valuation date	$ 45.38	$ 45.38
Performance term (in years)		3 years 0 months 0 days
Quarterly Dividends Paid Per Share	$ 0.455
Expected dividend yield		3.90%
Dividend Discount Factor		0.8943
LTIP Paragraph 2 [Abstract]
Share Based Compensation Arrangement By Share Based Payment Award Grant Date LTIP & RSU		Feb. 27, 2013
Shares Granted Under RSU		25,748
Stock Price On Restricted Stock Unit Grant Date, Minimum	$ 45.38	$ 45.38
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 1,900,000	$ 1,900,000
SOP Paragraph 1 [Abstract]
Unrecognized compensation cost, options	$ 300,000.0	$ 300,000.0
Unrecognized compensation cost, period for recognition		through 2014