Commitments and Contingencies, Textuals (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commitments and Contingencies Disclosure [Abstract]
Minimum rental commitments under operating lease, 2012	$ 7.5
Minimum rental commitments under operating lease, 2013	6.4
Minimum rental commitments under operating lease, 2014	3.6
Minimum rental commitments under operating lease, 2015	3.0
Minimum rental commitments under operating lease, 2016	2.3
Minimum rental commitments under operating lease, thereafter	33.0
Rental expense	$ 10.0	$ 9.9	$ 7.3

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within one year of the balance sheet date relating to leases defined as operating.

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For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fifth year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fourth year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the third year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the second year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due after the fifth year from the balance sheet date on leases defined as operating.

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