Severance Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Notes To Consolidated Financial Statements [Abstract]
Description Of Postemployment Benefits		Severance Benefits NU recorded severance benefit expenses of $0.7 million and $6.5 million associated with the partial outsourcing of information technology functions and ongoing post-merger integration for the three and nine months ended September 30, 2014, respectively, and $9.2 million for the three and nine months ended September 30, 2013. As of September 30, 2014 and December 31, 2013, the severance accrual totaled $6.4 million and $14.7 million, respectively, and was included in Other Current Liabilities on the balance sheets.
Postemployment Benefits Period Expense	$ 0.7	$ 6.5	$ 9.2
Postemployment Benefits Liability Current And Noncurrent	$ 6.4	$ 6.4		$ 14.7