Long-Term Debt (Details) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2014
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity, Current	$ 175,000,000.0	$ 250,000,000.0
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.0625%
Debt Instrument, Covenant, Leverage Ratio	2
Debt Covenant, Minimum Net Income Requirement	$ 1.00
Debt Covenant, Minimum Tangible Net Worth	175,000,000.0
Letters of Credit Outstanding, Amount	3,700,000
Line of Credit Facility, Current Borrowing Capacity	$ 171,300,000
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%