Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Fair Values, Assets		$ 1,352	$ 224
Fair Values, Liabilities		36,267	21,034
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		1,100,000	500,000
Fair Values, Assets	[1]	1,135
Fair Values, Liabilities	[1]	254	281
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		1,185,453	1,002,350
Fair Values, Assets	[1]	35,419	23,251
Fair Values, Liabilities	[1]	37,645	23,687
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts	[2]	905,662	780,871
Fair Values, Assets	[1],[2]	33,732	20,622
Fair Values, Liabilities	[1],[2]	35,447	21,007
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		86,839	83,430
Fair Values, Assets	[1]	97	83
Fair Values, Liabilities	[1]	215	162
Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		102,495	55,128
Fair Values, Assets	[1]	88	263
Fair Values, Liabilities	[1]	997	336
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		60,757	38,853
Fair Values, Assets	[1]	532	243
Fair Values, Liabilities	[1]	33	167
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		29,700	44,068
Fair Values, Assets	[1]	970	2,040
Fair Values, Liabilities	[1]	953	2,015
Cash Flow Hedge [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		1,100,000	500,000
Fair Values, Assets	[1]	1,135
Fair Values, Liabilities	[1]	$ 254	$ 281

[1] Derivative assets and liabilities are reported with other assets or other liabilities, respectively, in the consolidated balance sheets.

[2] The notional amount represents both the customer accommodation agreements and offsetting agreements with unrelated financial institutions.