Fair Value (Fair value measurement recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Securities available for sale	$ 1,655,696	$ 1,578,434
U.S. government corporations and agencies
Assets
Securities available for sale	4,955	25,766
Mortgage-backed securities
Assets
Securities available for sale	1,275,093	1,242,702
Obligations of states and political subdivisions
Assets
Securities available for sale	362,107	295,982
Corporate debt securities
Assets
Securities available for sale	0	846
Equity securities
Assets
Securities available for sale	13,541	13,138
Level 1
Assets
Securities available for sale	530	519
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Level 1 \| Interest rate lock commitments
Assets
Derivative assets	0	0
Level 1 \| Forward commitments
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Level 2
Assets
Securities available for sale	1,653,269	1,575,030
Derivative assets	5,228	2,237
Liabilities
Derivative liabilities	16,606	8,401
Level 2 \| Interest rate lock commitments
Assets
Derivative assets	0	0
Level 2 \| Forward commitments
Assets
Derivative assets	209	523
Liabilities
Derivative liabilities	1,312	315
Level 3
Assets
Securities available for sale	1,897	2,885
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Level 3 \| Interest rate lock commitments
Assets
Derivative assets	6,239	3,168
Level 3 \| Forward commitments
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Level 3 \| Corporate debt securities
Assets
Securities available for sale	0	846
Recurring Basis
Assets
Total assets at fair value	1,667,372	1,584,362
Liabilities
Total liabilities at fair value	17,918	8,716
Recurring Basis \| Derivative financial instruments
Assets
Derivative assets	5,228	2,237
Liabilities
Derivative liabilities	16,606	8,401
Recurring Basis \| Interest rate lock commitments
Assets
Derivative assets	6,239	3,168
Recurring Basis \| Forward commitments
Assets
Derivative assets	209	523
Liabilities
Derivative liabilities	1,312	315
Recurring Basis \| U.S. government corporations and agencies
Assets
Securities available for sale	4,955	25,766
Recurring Basis \| Mortgage-backed securities
Assets
Securities available for sale	1,275,093	1,242,702
Recurring Basis \| Obligations of states and political subdivisions
Assets
Securities available for sale	362,107	295,982
Recurring Basis \| Corporate debt securities
Assets
Securities available for sale	0	846
Recurring Basis \| Equity securities
Assets
Securities available for sale	13,541	13,138
Recurring Basis \| Level 1
Assets
Total assets at fair value	530	519
Liabilities
Total liabilities at fair value	0	0
Recurring Basis \| Level 1 \| Derivative financial instruments
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Level 1 \| Interest rate lock commitments
Assets
Derivative assets	0	0
Recurring Basis \| Level 1 \| Forward commitments
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Level 1 \| U.S. government corporations and agencies
Assets
Securities available for sale	530	519
Recurring Basis \| Level 1 \| Mortgage-backed securities
Assets
Securities available for sale	0	0
Recurring Basis \| Level 1 \| Obligations of states and political subdivisions
Assets
Securities available for sale	0	0
Recurring Basis \| Level 1 \| Corporate debt securities
Assets
Securities available for sale	0	0
Recurring Basis \| Level 1 \| Equity securities
Assets
Securities available for sale	0	0
Recurring Basis \| Level 2
Assets
Total assets at fair value	1,658,706	1,577,790
Liabilities
Total liabilities at fair value	17,918	8,716
Recurring Basis \| Level 2 \| Derivative financial instruments
Assets
Derivative assets	5,228	2,237
Liabilities
Derivative liabilities	16,606	8,401
Recurring Basis \| Level 2 \| Interest rate lock commitments
Assets
Derivative assets	0	0
Recurring Basis \| Level 2 \| Forward commitments
Assets
Derivative assets	209	523
Liabilities
Derivative liabilities	1,312	315
Recurring Basis \| Level 2 \| U.S. government corporations and agencies
Assets
Securities available for sale	4,425	25,247
Recurring Basis \| Level 2 \| Mortgage-backed securities
Assets
Securities available for sale	1,273,196	1,240,663
Recurring Basis \| Level 2 \| Obligations of states and political subdivisions
Assets
Securities available for sale	362,107	295,982
Recurring Basis \| Level 2 \| Corporate debt securities
Assets
Securities available for sale	0	0
Recurring Basis \| Level 2 \| Equity securities
Assets
Securities available for sale	13,541	13,138
Recurring Basis \| Level 3
Assets
Total assets at fair value	8,136	6,053
Liabilities
Total liabilities at fair value	0	0
Recurring Basis \| Level 3 \| Derivative financial instruments
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Level 3 \| Interest rate lock commitments
Assets
Derivative assets	6,239	3,168
Recurring Basis \| Level 3 \| Forward commitments
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Recurring Basis \| Level 3 \| U.S. government corporations and agencies
Assets
Securities available for sale	0	0
Recurring Basis \| Level 3 \| Mortgage-backed securities
Assets
Securities available for sale	1,897	2,039
Recurring Basis \| Level 3 \| Obligations of states and political subdivisions
Assets
Securities available for sale	0	0
Recurring Basis \| Level 3 \| Corporate debt securities
Assets
Securities available for sale	0	846
Recurring Basis \| Level 3 \| Equity securities
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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