Long-Term Debt (Details)	6 Months Ended
	Jun. 30, 2016 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity, Current		$ 250,000,000
Line of Credit Facility, Maximum Borrowing Capacity, Period 2	$ 200,000,000
Line of Credit Facility, Maximum Borrowing Capacity, Period 3	$ 175,000,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.0625%
Debt Instrument, Covenant, Leverage Ratio	2
Debt Covenant, Minimum Net Income Requirement	$ 1
Debt Instrument, Minimum Tangible Net Worth	200,000,000
letters of credit outstanding on a line of credit	5,500,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 194,500,000
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.625%
Prime Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%