Fair Value Measurements (Details) (Recurring basis, USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value
Assets (Liabilities) at fair value
Nonqualified deferred compensation assets	$ 4,168	$ 3,653
Nonqualified deferred compensation liability	(4,168)	(3,653)
Non-designated derivatives assets	94	839
Designated derivatives liability	(696)
Non-designated derivatives liability	(126)	(336)
Contingent consideration for acquisition of business	(46,923)	(71,460)
Level 1
Assets (Liabilities) at fair value
Nonqualified deferred compensation assets	4,168	3,653
Nonqualified deferred compensation liability	(4,168)	(3,653)
Level 2
Assets (Liabilities) at fair value
Non-designated derivatives assets	94	839
Designated derivatives liability	(696)
Non-designated derivatives liability	(126)	(336)
Level 3
Assets (Liabilities) at fair value
Contingent consideration for acquisition of business	$ (46,923)	$ (71,460)