Agreement and Plan of Merger (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 13, 2016	Mar. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)		$ 1	$ 1
Subsequent Event [Member] | Parent Company [Member]
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)	$ 1.00
Share price at the time of the Merger (in dollars per share)	$ 55.37
Additional contingency fees paid upon the completion of the Merger	$ 12.0