Commitments And Contingencies (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Oct. 29, 2012 Subsequent Event [Member]
Commitments And Guarantees [Line Items]
Operating Leases agreements, expiration date			Various dates through 2023
Rental expense relating to operating leases	$ 5,992	$ 3,913	$ 17,339	$ 11,109
Unfunded commitments for capital contributions	6,489		6,489
Acquisition amount					11,100
Acquisition assets amount	$ 645,000		$ 645,000