Fair Value Measurements (Details) (USD $) In Thousands	Jun. 30, 2011
Fair Value Measurements (Textuals) [Abstract]
Cost basis of the investment funds	$ 18,639
Fair Value Measurements on Recurring Basis [Member]
Assets:
Deferred compensation plan asset	18,798
Total assets at fair value	18,798
Liabilities:
Deferred compensation plan liability	22,691
Total liabilities at fair value	22,691
Fair Value Measurements on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Deferred compensation plan asset	16,032
Total assets at fair value	16,032
Liabilities:
Deferred compensation plan liability	22,691
Fair Value Measurements on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2)
Assets:
Deferred compensation plan asset	2,766
Total assets at fair value	2,766
Fair Value Measurements on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3)
Assets:
Deferred compensation plan asset	0
Total assets at fair value	0
Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Total liabilities at fair value	$ 22,691