Non-Cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			$ 35,972
Transferred loans to mortgage servicing assets	$ 5,758	$ 3,614	2,717
Transfer of premises and equipment pending disposal to other assets, book value		$ 1,805	$ 1,448
Class A Common Stock | Mountain West Bank
Class of Stock
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares			1,378,230