Note 7 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Loans Held-for-sale [Member] \| Changes Measurement [Member] \| Fair Value, Nonrecurring [Member]
Assets, Fair Value Adjustment	$ 0	$ 0

Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

No definition available.

Name:	us-gaap_AssetsFairValueAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration