Revolving Credit Facility (Details)	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014
Line of Credit Facility [Line Items]
Actual net worth for compliance	$ 178,900,000
Minimum net worth required for compliance	$ 95,000,000
Ratio of total liability to net worth	0.3
Maximum ratio of total liability to net worth for compliance	2
Actual working capital for compliance	$ 80,800,000
Minimum working capital for compliance	40,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility maximum borrowings	30,000,000.0
Standby letter of credit	800,000
Borrowings available under the revolving credit facility	$ 29,200,000
Frequency of periodic payments	monthly
Fees associated with unused portion of committed amount	$ 0
Borrowings outstanding under revolving credit facility	$ 0
Weighted average interest rate	2.60%	2.70%
Revolving Credit Facility [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Stated percentage	2.50%