Loans, Changes in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Change in the allowance for unfunded commitments
Balance at beginning of period	$ 25,000
Balance at end of period	24,000	$ 25,000
Allowance for Unfunded Commitments:
Change in the allowance for unfunded commitments
Balance at beginning of period	25,400	24,400
Provision for unfunded commitments	(1,000)	1,000
Balance at end of period	$ 24,400	$ 25,400