Finance Receivables - Information regarding delinquency rates with respect to contracts and direct loans (Details 4) (Finance receivables, USD $)	Dec. 31, 2014	Dec. 31, 2013
Contracts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross Balance Outstanding	$ 431,877,085	$ 395,782,832
31 - 60 days	21,749,891	18,523,310
31 - 60 days (in percentage)	5.04%	4.68%
61 - 90 days	6,103,607	4,829,999
61 - 90 days (in percentage)	1.41%	1.22%
Over 90 days	3,180,951	2,106,854
Over 90 days (in percentage)	0.74%	0.53%
Total	31,034,449	25,460,163
Total (in percentage)	7.19%	6.43%
Direct Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross Balance Outstanding	11,680,909	11,301,076
31 - 60 days	164,347	176,446
31 - 60 days (in percentage)	1.41%	1.56%
61 - 90 days	59,043	40,887
61 - 90 days (in percentage)	0.51%	0.36%
Over 90 days	46,776	29,046
Over 90 days (in percentage)	0.40%	0.26%
Total	$ 270,166	$ 246,379
Total (in percentage)	2.31%	2.18%

Represents gross amount of notes receivable excluding chapter 13 bankrupt accounts.

No definition available.

Name:	nick_NotesReceivableGrossAmountExcludingChapter13BankruptAccounts
Namespace Prefix:	nick_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents percentage of financing receivables that are less than 60 days past due but more than 29 days past due.

+ References

No definition available.

+ Details

Name:	nick_PercentageOfFinancingReceivableRecordedInvestment30To59DaysPastDue
Namespace Prefix:	nick_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents percentage of financing receivables that are less than 90 days past due but more than 59 days past due.

+ References

No definition available.

+ Details

Name:	nick_PercentageOfFinancingReceivableRecordedInvestment60To89DaysPastDue
Namespace Prefix:	nick_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents percentage of financing receivables that are equal to or greater than 90 days past due.

+ References

No definition available.

+ Details

Name:	nick_PercentageOfFinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
Namespace Prefix:	nick_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents percentage of recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

No definition available.

+ Details

Name:	nick_PercentageOfFinancingReceivableRecordedInvestmentPastDueTotal
Namespace Prefix:	nick_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Financing receivables that are less than 60 days past due but more than 29 days past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing receivables that are less than 90 days past due but more than 59 days past due.

+ References

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing receivables that are equal to or greater than 90 days past due.

+ References

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant