Subsequent Events (Details) (New agreement, 2012 Credit Agreement, USD $) In Millions, unless otherwise specified	1 Months Ended
	May 31, 2012 Y	May 02, 2012
New agreement | 2012 Credit Agreement
Subsequent Events
Maximum borrowing capacity		$ 500
Term of revolving credit facility (in years)	5
Available credit		491.2
Variable interest base rate	applicable margin over LIBOR or a base rate
Minimum borrowing amount in excess of which subsidiary guarantees other debt borrowed		$ 250