Commitments And Contingencies (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012
Lease expiry period	seven years and seven months
Coverage under its relevant insurance policies	$ 350,000
201 Spear Street [Member]
Operating lease space, in square feet	34,000
525 Market Street [Member]
Operating lease space, in square feet	57,000
Lease term, in years	7
Optional lease extension term, in years	5
Tenant improvement allowance	2,400,000
Outstanding letters of credit collateralized by restricted cash	5,100,000
Oakbrook Terrace [Member]
Operating lease space, in square feet	15,000
Tenant improvement allowance	800,000
Outstanding letters of credit collateralized by restricted cash	$ 800,000
India [Member]
Operating lease space, in square feet	9,000
Lease expiry period	December 2015
Maximum [Member] | 201 Spear Street [Member]
Lease expiry period	May 2013
Minimum [Member] | 201 Spear Street [Member]
Lease expiry period	July 2012