Fair Value Measurement and Fair Value of Financial Instruments (Financial Assets and Liabilities Measurement on Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Investment securities available-for-sale
Equity securities		$ 31,900
Derivative
Derivative assets	$ 81,456	66,146
Derivative liabilities	114,542	74,935
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investment securities available-for-sale
Available-for-sale investment securities	629,270	661,015
Equity securities	20,431
Total investments in tax credit and other investments	20,431
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate swaps and options
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign exchange forwards, spot and swaps
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | RPAs
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity warrants
Derivative
Derivative assets	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commodity swaps and options
Derivative
Derivative assets	0
Derivative liabilities	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate swaps
Derivative
Derivative liabilities		0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	629,270	640,280
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other securities
Investment securities available-for-sale
Available-for-sale investment securities		20,735
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investment securities available-for-sale
Available-for-sale investment securities	2,078,174	2,355,737
Equity securities	10,498
Total investments in tax credit and other investments	10,498
Derivative
Derivative assets	80,808	65,467
Derivative liabilities	114,542	74,935
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps and options
Derivative
Derivative assets	64,225	58,633
Derivative liabilities	100,025	57,958
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign exchange forwards, spot and swaps
Derivative
Derivative assets	11,724	5,840
Derivative liabilities	11,281	10,170
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | RPAs
Derivative
Derivative assets	1	1
Derivative liabilities	77	8
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Equity warrants
Derivative
Derivative assets	1,230	993
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Commodity swaps and options
Derivative
Derivative assets	3,628
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps
Derivative
Derivative liabilities		6,799
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	240,042	203,392
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	337,237	318,957
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	936,447	1,190,271
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	73,619	99,982
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	7,835	9,117
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	11,001	37,003
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	459,433	486,408
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Asset-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	12,560
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other securities
Investment securities available-for-sale
Available-for-sale investment securities		10,607
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Equity securities	0
Total investments in tax credit and other investments	0
Derivative
Derivative assets	648	679
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Interest rate swaps and options
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Foreign exchange forwards, spot and swaps
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | RPAs
Derivative
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Equity warrants
Derivative
Derivative assets	648	679
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Commodity swaps and options
Derivative
Derivative assets	0
Derivative liabilities	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Interest rate swaps
Derivative
Derivative liabilities		0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Asset-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Other securities
Investment securities available-for-sale
Available-for-sale investment securities		0
Fair Value, Measurements, Recurring | Fair Value Measurements
Investment securities available-for-sale
Available-for-sale investment securities	2,707,444	3,016,752
Equity securities	30,929
Total investments in tax credit and other investments	30,929
Derivative
Derivative assets	81,456	66,146
Derivative liabilities	114,542	74,935
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps and options
Derivative
Derivative assets	64,225	58,633
Derivative liabilities	100,025	57,958
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign exchange forwards, spot and swaps
Derivative
Derivative assets	11,724	5,840
Derivative liabilities	11,281	10,170
Fair Value, Measurements, Recurring | Fair Value Measurements | RPAs
Derivative
Derivative assets	1	1
Derivative liabilities	77	8
Fair Value, Measurements, Recurring | Fair Value Measurements | Equity warrants
Derivative
Derivative assets	1,878	1,672
Fair Value, Measurements, Recurring | Fair Value Measurements | Commodity swaps and options
Derivative
Derivative assets	3,628
Derivative liabilities	3,159
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps
Derivative
Derivative liabilities		6,799
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	629,270	640,280
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	240,042	203,392
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	337,237	318,957
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	936,447	1,190,271
Fair Value, Measurements, Recurring | Fair Value Measurements | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	73,619	99,982
Fair Value, Measurements, Recurring | Fair Value Measurements | Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	7,835	9,117
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	11,001	37,003
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	459,433	486,408
Fair Value, Measurements, Recurring | Fair Value Measurements | Asset-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	$ 12,560
Fair Value, Measurements, Recurring | Fair Value Measurements | Other securities
Investment securities available-for-sale
Available-for-sale investment securities		$ 31,342