Cash and Cash Equivalents (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Cash and Cash Equivalents [Abstract]
Cash	$ 362,200,000	$ 330,800,000
Investments in cash equivalents	6,000,000	45,900,000
Restricted cash	1,496,000	1,574,000
Restricted cash outstanding, letters of credit used for collateral	1,000,000
Restricted cash guaranteed, investment certificate for collateral	200,000	200,000
Restricted cash and cash equivalents, foreign tender	$ 300,000	$ 400,000