Derivative Instruments and Balance Sheet Offsetting (Notional Amount and Fair Value) (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Derivative instruments
Notional Amount	$ 951,447,000	$ 90,911,000
Gross Derivative Assets	17,196,000	2,018,000
Gross Derivative Liabilities	15,970,000	1,979,000
Credit valuation adjustments for counterparty credit risk	745,000	0
Not designated as hedging | Customer-initiated derivatives [Member]
Derivative instruments
Notional Amount	559,458,000	0
Gross Derivative Assets	12,250,000	0
Gross Derivative Liabilities	12,787,000	0
Not designated as hedging | Forward contracts related to mortgage loans to be delivered for sale [Member]
Derivative instruments
Notional Amount	197,874,000	33,787,000
Gross Derivative Assets	89,000	144,000
Gross Derivative Liabilities	944,000	57,000
Not designated as hedging | Interest rate lock commitments [Member]
Derivative instruments
Notional Amount	157,743,000	23,421,000
Gross Derivative Assets	2,674,000	42,000
Gross Derivative Liabilities	56,000	90,000
Not designated as hedging | Power Equity CD [Member]
Derivative instruments
Notional Amount	36,372,000	33,703,000
Gross Derivative Assets	2,183,000	1,832,000
Gross Derivative Liabilities	$ 2,183,000	$ 1,832,000