Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loss Contingencies [Line Items]
Operating leases, rent expense	$ 541,000	$ 270,000	$ 246,000
Surety Bond [Member]
Loss Contingencies [Line Items]
Surety bonds	$ 10,300,000	$ 6,900,000