Derivative and Hedging Activities, Derivative Instruments Not Designated as Hedging Instruments (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Trading assets | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 2,198,794	$ 2,039,323
Fair Value	26,837	33,671
Trading assets | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	130,191	109,675
Fair Value	3,053	2,002
Trading assets | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	424,996	127,582
Fair Value	18,539	16,725
Trading liabilities | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	2,198,794	2,039,323
Fair Value	(26,469)	(33,188)
Trading liabilities | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	122,307	106,251
Fair Value	(3,033)	(1,943)
Trading liabilities | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	396,754	128,368
Fair Value	(17,310)	(15,972)
Other assets | Interest rate lock commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	354,075	285,345
Fair Value	2,729	206
Other assets | Forward commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	243,500	179,600
Fair Value	234	2,908
Other assets | Purchased options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	53,074	80,554
Fair Value	1,434	2,576
Other liabilities | Written options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	53,074	80,554
Fair Value	$ (1,434)	$ (2,576)