Term Loan and Line of Credit (Narrative) (Details) - Credit Agreement - USD ($)	3 Months Ended		6 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2018	May 31, 2017
Line of Credit Facility [Line Items]
Principal payments for year one	$ 1,500,000		$ 1,500,000
Principal payments for year two	2,300,000		2,300,000
Principal payments for year three	3,100,000		3,100,000
Principal payments for year four	$ 3,900,000		$ 3,900,000
Interest rate of credit facilities	3.44%		3.44%
Debt issuance cost	$ 1,800,000		$ 1,800,000
Amortization of debt issuance costs	100,000	$ 100,000	200,000	$ 200,000
Revolving line of credit
Line of Credit Facility [Line Items]
Term loan	123,750,000		123,750,000
Unsecured credit facility	150,000,000		150,000,000
Additional borrowing capacity available	125,000,000		125,000,000
Fair value of term loan	120,700,000		120,700,000
Due in next 12 months	6,200,000		6,200,000
Line of credit facility outstanding amount	0		0
Swing line loans
Line of Credit Facility [Line Items]
Term loan	25,000,000		25,000,000
Letter of credit
Line of Credit Facility [Line Items]
Term loan	25,000,000		25,000,000
Line of credit facility outstanding amount	$ 1,300,000		$ 1,300,000