Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Fair Values, Assets	[1]	$ 36,479	$ 23,251
Fair Values, Liabilities	[1]	36,336	23,968
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		800,000	500,000
Fair Values, Assets	[2]	1,808
Fair Values, Liabilities	[2]		281
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		800,000	500,000
Fair Values, Assets	[2]	1,808
Fair Values, Liabilities	[2]		281
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		1,098,014	1,002,350
Fair Values, Assets	[2]	34,671	23,251
Fair Values, Liabilities	[2]	36,336	23,687
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts	[3]	826,734	780,871
Fair Values, Assets	[2],[3]	32,510	20,622
Fair Values, Liabilities	[2],[3]	33,838	21,007
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		89,723	83,430
Fair Values, Assets	[2]	112	83
Fair Values, Liabilities	[2]	217	162
Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		83,935	55,128
Fair Values, Assets	[2]	51	263
Fair Values, Liabilities	[2]	979	336
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		60,607	38,853
Fair Values, Assets	[2]	697	243
Fair Values, Liabilities	[2]	24	167
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional Amounts		37,015	44,068
Fair Values, Assets	[2]	1,301	2,040
Fair Values, Liabilities	[2]	$ 1,278	$ 2,015

[1] For further disaggregation of derivative assets and liabilities, see Note 6 - Derivatives.

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

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