Credit Facilities (Narrative) (Details) - Revolving Credit Facility [Member]	Jul. 27, 2017	Apr. 30, 2018 USD ($) letter_of_credit	Mar. 31, 2018 USD ($) letter_of_credit	Nov. 10, 2015 USD ($)
Line of Credit Facility [Line Items]
Long-term line of credit			$ 0
Subsequent Event [Member]
Line of Credit Facility [Line Items]
Long-term line of credit		$ 0
London Interbank Offered Rate (LIBOR) [Member] | Seventh Amendment [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.75%
Sixth Amendment [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 15,000,000.00
LIBOR Rate Loan [Member]
Line of Credit Facility [Line Items]
Standby letters of credit, total amount outstanding			$ 500,000
Number of standby letters of credit outstanding | letter_of_credit			1
Remaining borrowing capacity			$ 7,200,000
LIBOR Rate Loan [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Standby letters of credit, total amount outstanding		$ 500,000
Number of standby letters of credit outstanding | letter_of_credit		1