Derivative and Hedging Activities, Derivative Instruments Not Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Not Designated as Hedging Instrument | Trading assets | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 2,712,813	$ 2,183,687
Derivative, Fair Value, Net	68,916	28,494
Not Designated as Hedging Instrument | Trading assets | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	124,137	124,851
Derivative, Fair Value, Net	1,974	2,495
Not Designated as Hedging Instrument | Trading assets | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	401,849	457,868
Derivative, Fair Value, Net	69,439	38,686
Not Designated as Hedging Instrument | Trading liabilities | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	2,712,813	2,183,687
Derivative, Fair Value, Net	(68,103)	(28,035)
Not Designated as Hedging Instrument | Trading liabilities | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	119,748	118,094
Derivative, Fair Value, Net	(1,840)	(2,339)
Not Designated as Hedging Instrument | Trading liabilities | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	401,968	457,108
Derivative, Fair Value, Net	(68,997)	(37,286)
Not Designated as Hedging Instrument | Other assets | Interest rate lock commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	259,762	222,736
Derivative, Fair Value, Net	1,685	1,538
Not Designated as Hedging Instrument | Other assets | Forward commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	271,561
Derivative, Fair Value, Net	1,352
Not Designated as Hedging Instrument | Other assets | Purchased options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	21,269	31,063
Derivative, Fair Value, Net	577	1,175
Not Designated as Hedging Instrument | Other liabilities | Forward commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount		164,567
Derivative, Fair Value, Net		(313)
Not Designated as Hedging Instrument | Other liabilities | Written options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	21,269	31,063
Derivative, Fair Value, Net	(577)	(1,175)
Designated as Hedging Instrument | Other assets | interest rate product [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	500,000	0
Derivative, Fair Value, Net	$ 4,902	$ 0