Interest Rate Swap Agreements (Detail Textuals) - Interest Rate Swap - USD ($) $ in Millions		1 Months Ended
Jun. 13, 2017	Jul. 30, 2017
Derivatives, Fair Value [Line Items]
Derivative notional amount	$ 25.0	$ 25.0
Fixed interest rate	1.00%	0.87%
Interest rate swap agreements, effective date	Jun. 13, 2012	Jul. 30, 2012

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Date the interest rate swap agreement become effective, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	nick_DerivativeEffectiveDate
Namespace Prefix:	nick_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativesFairValueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: