Investment Securities Schedule of Debt Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investment securities available-for-sale:
Amortized Cost	$ 1,018,774	$ 1,161,633
Unrealized Gains	2,437	5,072
Unrealized Losses	(27,146)	(17,171)
Available-for-sale, fair value	994,065	1,149,534
Investment securities held-to-maturity:
Amortized Cost	70,438	74,576
Unrealized Gains	2	0
Unrealized Losses	(1,845)	(795)
Fair Value	68,595	73,781
Equity Securities, FV-NI [Abstract]
Amortized cost	14,228	20,794
Fair Value	14,228	20,794
U.S. government and agencies
Investment securities available-for-sale:
Amortized Cost	30,043	35,132
Unrealized Gains	0	0
Unrealized Losses	(929)	(833)
Available-for-sale, fair value	29,114	34,299
Investment securities held-to-maturity:
Amortized Cost	9,898
Unrealized Gains	2
Unrealized Losses	0
Fair Value	9,900
Government-sponsored entities
Investment securities available-for-sale:
Amortized Cost	211,655	305,101
Unrealized Gains	0	22
Unrealized Losses	(3,952)	(2,622)
Available-for-sale, fair value	207,703	302,501
Municipal bonds
Investment securities available-for-sale:
Amortized Cost	309,837	299,647
Unrealized Gains	2,223	4,559
Unrealized Losses	(3,101)	(1,148)
Available-for-sale, fair value	308,959	303,058
Mortgage-backed securities
Investment securities available-for-sale:
Amortized Cost	467,239	521,753
Unrealized Gains	214	491
Unrealized Losses	(19,164)	(12,568)
Available-for-sale, fair value	448,289	509,676
Investment securities held-to-maturity:
Amortized Cost	60,540	74,576
Unrealized Gains	0	0
Unrealized Losses	(1,845)	(795)
Fair Value	58,695	73,781
Other
Equity Securities, FV-NI [Abstract]
Amortized cost	14,228
Fair Value	14,228
Money market mutual funds
Equity Securities, FV-NI [Abstract]
Amortized cost	14,228	20,794
Fair Value	$ 14,228	$ 20,794

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