Fair Value (Fair value measurement recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Securities available for sale	$ 2,093,385	$ 1,845,864
Level 1
Assets
Securities available for sale	3,505	517
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Level 2
Assets
Securities available for sale	2,089,880	1,843,123
Derivative assets	3,386	3,222
Liabilities
Derivative liabilities	6,309	7,027
Level 3
Assets
Securities available for sale	0	2,224
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Interest rate lock commitments \| Level 1
Assets
Derivative assets	0	0
Interest rate lock commitments \| Level 2
Assets
Derivative assets	0	0
Interest rate lock commitments \| Level 3
Assets
Derivative assets	2,463	2,790
Forward commitments \| Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Forward commitments \| Level 2
Assets
Derivative assets	237	2,546
Liabilities
Derivative liabilities	261	266
Forward commitments \| Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
U.S. government corporations and agencies
Assets
Securities available for sale	7,415	4,700
Mortgage-backed securities
Assets
Securities available for sale	1,565,400	1,290,500
Obligations of states and political subdivisions
Assets
Securities available for sale	503,974	536,144
Equity securities
Assets
Securities available for sale	16,596	14,520
Recurring Basis
Assets
Total assets at fair value	2,099,471	1,854,422
Liabilities
Total liabilities at fair value	6,570	7,293
Recurring Basis \| Level 1
Assets
Total assets at fair value	3,505	517
Liabilities
Total liabilities at fair value	0	0
Recurring Basis \| Level 2
Assets
Total assets at fair value	2,093,503	1,848,891
Liabilities
Total liabilities at fair value	6,570	7,293
Recurring Basis \| Level 3
Assets
Total assets at fair value	2,463	5,014
Liabilities
Total liabilities at fair value	0	0
Recurring Basis \| Derivative Financial Instruments
Assets
Derivative assets	3,386	3,222
Liabilities
Derivative liabilities	6,309	7,027
Recurring Basis \| Derivative Financial Instruments \| Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Derivative Financial Instruments \| Level 2
Assets
Derivative assets	3,386	3,222
Liabilities
Derivative liabilities	6,309	7,027
Recurring Basis \| Derivative Financial Instruments \| Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Interest rate lock commitments
Assets
Derivative assets	2,463	2,790
Recurring Basis \| Interest rate lock commitments \| Level 1
Assets
Derivative assets	0	0
Recurring Basis \| Interest rate lock commitments \| Level 2
Assets
Derivative assets	0	0
Recurring Basis \| Interest rate lock commitments \| Level 3
Assets
Derivative assets	2,463	2,790
Recurring Basis \| Forward commitments
Assets
Derivative assets	237	2,546
Liabilities
Derivative liabilities	261	266
Recurring Basis \| Forward commitments \| Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Forward commitments \| Level 2
Assets
Derivative assets	237	2,546
Liabilities
Derivative liabilities	261	266
Recurring Basis \| Forward commitments \| Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| U.S. government corporations and agencies
Assets
Securities available for sale	7,415	4,700
Recurring Basis \| U.S. government corporations and agencies \| Level 1
Assets
Securities available for sale	3,505	517
Recurring Basis \| U.S. government corporations and agencies \| Level 2
Assets
Securities available for sale	3,910	4,183
Recurring Basis \| U.S. government corporations and agencies \| Level 3
Assets
Securities available for sale	0	0
Recurring Basis \| Mortgage-backed securities
Assets
Securities available for sale	1,565,400	1,290,500
Recurring Basis \| Mortgage-backed securities \| Level 1
Assets
Securities available for sale	0	0
Recurring Basis \| Mortgage-backed securities \| Level 2
Assets
Securities available for sale	1,565,400	1,288,276
Recurring Basis \| Mortgage-backed securities \| Level 3
Assets
Securities available for sale	0	2,224
Recurring Basis \| Obligations of states and political subdivisions
Assets
Securities available for sale	503,974	536,144
Recurring Basis \| Obligations of states and political subdivisions \| Level 1
Assets
Securities available for sale	0	0
Recurring Basis \| Obligations of states and political subdivisions \| Level 2
Assets
Securities available for sale	503,974	536,144
Recurring Basis \| Obligations of states and political subdivisions \| Level 3
Assets
Securities available for sale	0	0
Recurring Basis \| Corporate debt securities
Assets
Securities available for sale	0
Recurring Basis \| Corporate debt securities \| Level 1
Assets
Securities available for sale	0
Recurring Basis \| Corporate debt securities \| Level 2
Assets
Securities available for sale	0
Recurring Basis \| Corporate debt securities \| Level 3
Assets
Securities available for sale	0
Recurring Basis \| Equity securities
Assets
Securities available for sale	16,596	14,520
Recurring Basis \| Equity securities \| Level 1
Assets
Securities available for sale	0	0
Recurring Basis \| Equity securities \| Level 2
Assets
Securities available for sale	16,596	14,520
Recurring Basis \| Equity securities \| Level 3
Assets
Securities available for sale	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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