Loans - Other (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Loans and Leases Receivable, Other Information [Abstract]
Net deferred loan origination fees and unamortized premium and discount	$ 18,300	$ 19,800
Non-accretable discount on acquired credit impaired loans	5,100	13,400
Accrued interest receivable on loans	6,600	7,300
Consumer and other [Member]
Loans and Leases Receivable, Other Information [Abstract]
Deposit Liabilities Reclassified as Loans Receivable	$ 74	$ 560
Reserved Based Energy Loans [Member]
Loans and Leases Receivable, Other Information [Abstract]
Percentage of total funded loans	0.90%	4.20%
Loans	$ 25,800	$ 32,300
Energy Related Service Industry Loans [Member]
Loans and Leases Receivable, Other Information [Abstract]
Percentage of total funded loans	3.40%	5.20%
Loans	$ 38,000	$ 291