Fair Value Measurements (Details) (Recurring basis, USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value
Assets (Liabilities) assets at fair value
Nonqualified deferred compensation assets	$ 3,587	$ 1,991
Nonqualified deferred compensation liability	(3,587)	(1,991)
Designated derivatives assets	450	1,117
Designated derivatives liabilities	(1,053)	(87)
Non-designated derivatives liabilities	(272)
Contingent, consideration for acquisition of business	(69,024)	(91,600)
Level 1
Assets (Liabilities) assets at fair value
Nonqualified deferred compensation assets	3,587	1,991
Nonqualified deferred compensation liability	(3,587)	(1,991)
Level 2
Assets (Liabilities) assets at fair value
Designated derivatives assets	450	1,117
Designated derivatives liabilities	(1,053)	(87)
Non-designated derivatives liabilities	(272)
Level 3
Assets (Liabilities) assets at fair value
Contingent, consideration for acquisition of business	$ (69,024)	$ (91,600)