Severance, Restructuring and Other Charges (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of severance, restructuring and other charges
Severance	$ 679	$ 2,455	$ 5,627	$ 11,079	$ 6,501
Lease exit charges	46	349	4,898	7	3,443
Asset impairment charges				275	1,746
Transaction related expenses	974		3,876	(592)	209
Severance, restructuring and other charges, net	$ 1,699	$ 2,804	$ 14,401	$ 10,769	$ 11,899

The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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The charge against earnings in the period, comprised of costs incurred associated with an exit or disposal activity other than for a discontinued operations as defined under generally accepted accounting principles. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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- Definition

The charge against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

+ References

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