Fair Value Measurements (Details) (Recurring basis, USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Fair Value
(Liabilities) assets at fair value
Nonqualified deferred compensation	$ (3,450)	$ (1,991)
Designated derivatives	159	1,117
Designated derivatives	(1,056)	(87)
Contingent, consideration for acquisition of business	(62,794)	(91,600)
Level 1
(Liabilities) assets at fair value
Nonqualified deferred compensation	(3,450)	(1,991)
Level 2
(Liabilities) assets at fair value
Designated derivatives	159	1,117
Designated derivatives	(1,056)	(87)
Level 3
(Liabilities) assets at fair value
Contingent, consideration for acquisition of business	$ (62,794)	$ (91,600)