Fair Value (Fair Value Measurement Recurring) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 2,433,623,000
Equity securities with a readily determinable fair value, fair value	17,086,000
Securities available for sale		$ 2,216,753,000
U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	31,951,000
Securities available for sale		5,328,000
Mortgage and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	2,026,698,000		$ 483,000
Securities available for sale		1,753,736,000
Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	374,974,000
Securities available for sale		441,015,000
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		16,674,000
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Securities available for sale	25,414,000	3,484,000
Level 1 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Level 1 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	6,539,000	3,933,000
Derivative liabilities	6,044,000	5,167,000
Securities available for sale	2,425,295,000	2,213,269,000
Level 2 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Level 2 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	80,000
Derivative liabilities	399,000	232,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Securities available for sale	0	0
Level 3 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	725,000	1,738,000
Level 3 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2,457,973,000	2,222,504,000
Total liabilities at fair value	6,443,000	5,399,000
Recurring Basis | U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	31,951,000
Securities available for sale		5,328,000
Recurring Basis | Mortgage and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	2,026,698,000
Securities available for sale		1,753,736,000
Recurring Basis | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	374,974,000
Securities available for sale		441,015,000
Recurring Basis | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value, fair value	17,086,000
Securities available for sale		16,674,000
Recurring Basis | Embedded Derivatives and Loan Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	6,539,000	3,933,000
Recurring Basis | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	725,000	1,738,000
Recurring Basis | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	80,000
Derivative liabilities	399,000	232,000
Recurring Basis | Cash Flow Hedges, Loan Swaps and Free Standing Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	6,044,000	5,167,000
Recurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	25,414,000	3,484,000
Total liabilities at fair value	0	0
Recurring Basis | Level 1 | U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	25,414,000
Securities available for sale		3,484,000
Recurring Basis | Level 1 | Mortgage and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Securities available for sale		0
Recurring Basis | Level 1 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Securities available for sale		0
Recurring Basis | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value, fair value	0
Securities available for sale		0
Recurring Basis | Level 1 | Embedded Derivatives and Loan Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 1 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 1 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Recurring Basis | Level 1 | Cash Flow Hedges, Loan Swaps and Free Standing Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Recurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2,431,834,000	2,217,282,000
Total liabilities at fair value	6,443,000	5,399,000
Recurring Basis | Level 2 | U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	6,537,000
Securities available for sale		1,844,000
Recurring Basis | Level 2 | Mortgage and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	2,026,698,000
Securities available for sale		1,753,736,000
Recurring Basis | Level 2 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	374,974,000
Securities available for sale		441,015,000
Recurring Basis | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value, fair value	17,086,000
Securities available for sale		16,674,000
Recurring Basis | Level 2 | Embedded Derivatives and Loan Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	6,539,000	3,933,000
Recurring Basis | Level 2 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 2 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	80,000
Derivative liabilities	399,000	232,000
Recurring Basis | Level 2 | Cash Flow Hedges, Loan Swaps and Free Standing Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	6,044,000	5,167,000
Recurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	725,000	1,738,000
Total liabilities at fair value	0	0
Recurring Basis | Level 3 | U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Securities available for sale		0
Recurring Basis | Level 3 | Mortgage and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Securities available for sale		0
Recurring Basis | Level 3 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Securities available for sale		0
Recurring Basis | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value, fair value	0
Securities available for sale		0
Recurring Basis | Level 3 | Embedded Derivatives and Loan Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 3 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	725,000	1,738,000
Recurring Basis | Level 3 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Recurring Basis | Level 3 | Cash Flow Hedges, Loan Swaps and Free Standing Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ 0	$ 0