Parent Company Condensed Financial Statements (Details Textual) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Dividends That Could Be Paid Without Regulatory Approvals	$ 13.9

Represents the amount of dividends that the bank could pay without regulatory approval.

No definition available.

Name:	lark_DividendsThatCouldBePaidWithoutRegulatoryApprovals
Namespace Prefix:	lark_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant