Interest Rate Swap Agreements - Summary of average variable rates received and average fixed rates paid under the swap (Details 2) (Swap)	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Swap
Derivative [Line Items]
Average variable rate received	0.22%	0.00%
Average fixed rate paid	0.94%	0.00%

Average variable interest rate related to the group of interest rate derivatives.

No definition available.

Name:	nick_DerivativeAverageVariableInterestRateReceived
Namespace Prefix:	nick_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration