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.

No definition available.

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

Commitments and Contingencies Legal Proceedings (Details) - Kelly Logging Inc. v. First Interstate Bank [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss Contingencies
Loss Contingency, Loss in Period	$ 4,150
Settled Litigation [Member]
Loss Contingencies
Litigation Settlement, Expense		$ 5,000	$ 4,000