Fair Value (Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012 Forward Contracts [Member]	Jun. 30, 2012 2.25% Senior convertible debentures [Member]	Mar. 31, 2012 2.25% Senior convertible debentures [Member]	Dec. 31, 2011 2.25% Senior convertible debentures [Member]	Mar. 26, 2011 2.25% Senior convertible debentures [Member]	Jun. 30, 2012 Recurring Basis [Member]	Dec. 31, 2011 Recurring Basis [Member]	Jun. 30, 2012 Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets Level 1 [Member]	Dec. 31, 2011 Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets Level 1 [Member]	Jun. 30, 2012 Recurring Basis [Member] Significant Other Observable Inputs Level 2 [Member]	Dec. 31, 2011 Recurring Basis [Member] Significant Other Observable Inputs Level 2 [Member]	Jun. 30, 2012 Recurring Basis [Member] Significant Unobservable Inputs Level 3 [Member]	Dec. 31, 2011 Recurring Basis [Member] Significant Unobservable Inputs Level 3 [Member]	Jun. 30, 2012 Time Deposits [Member] Recurring Basis [Member]	Dec. 31, 2011 Time Deposits [Member] Recurring Basis [Member]	Jun. 30, 2012 Time Deposits [Member] Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets Level 1 [Member]	Dec. 31, 2011 Time Deposits [Member] Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets Level 1 [Member]	Jun. 30, 2012 Time Deposits [Member] Recurring Basis [Member] Significant Other Observable Inputs Level 2 [Member]	Dec. 31, 2011 Time Deposits [Member] Recurring Basis [Member] Significant Other Observable Inputs Level 2 [Member]	Jun. 30, 2012 Time Deposits [Member] Recurring Basis [Member] Significant Unobservable Inputs Level 3 [Member]	Dec. 31, 2011 Time Deposits [Member] Recurring Basis [Member] Significant Unobservable Inputs Level 3 [Member]	Jun. 30, 2012 Auction Rate Securities [Member] Recurring Basis [Member]	Dec. 31, 2011 Auction Rate Securities [Member] Recurring Basis [Member]	Jun. 30, 2012 Auction Rate Securities [Member] Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets Level 1 [Member]	Dec. 31, 2011 Auction Rate Securities [Member] Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets Level 1 [Member]	Jun. 30, 2012 Auction Rate Securities [Member] Recurring Basis [Member] Significant Other Observable Inputs Level 2 [Member]	Dec. 31, 2011 Auction Rate Securities [Member] Recurring Basis [Member] Significant Other Observable Inputs Level 2 [Member]	Jun. 30, 2012 Auction Rate Securities [Member] Recurring Basis [Member] Significant Unobservable Inputs Level 3 [Member]	Dec. 31, 2011 Auction Rate Securities [Member] Recurring Basis [Member] Significant Unobservable Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life policies						$ 14,663	$ 19,520	$ 0	$ 0	$ 14,663	$ 19,520	$ 0	$ 0
Hedge contract						70	5	0	0	70	5	0	0
Total assets measured at fair value						21,356	35,935	0	0	21,356	24,884	0	11,051	6,623	5,359	0	0	6,623	5,359	0	0	0	11,051	0	0	0	0	0	11,051
Contingent consideration						0	0	0	0	0	0	0	0
Total liabilities measured at fair value						0	0	0	0	0	0	0	0
Interest rate on debt (as a percent)		2.25%	2.25%	2.25%	2.25%
Fair value of debt		350,870
Hedge gains recorded	(1,431)
Outstanding forward contract, fair value	$ 70