Securities - Amortized Cost and Fair Value of Securities Available for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Amortized cost and fair value of securities available for sale
Amortized Cost	$ 1,254,258	$ 1,264,529
Gross Unrealized Gains	18,463	4,517
Gross Unrealized Losses	(4,441)	(18,269)
Fair Value	1,268,280	1,250,777
Obligations of other U.S. Government agencies and corporations
Amortized cost and fair value of securities available for sale
Amortized Cost	2,527	2,536
Gross Unrealized Gains	20	13
Gross Unrealized Losses	(8)	(38)
Fair Value	2,539	2,511
Obligations of states and political subdivisions
Amortized cost and fair value of securities available for sale
Amortized Cost	169,123	200,798
Gross Unrealized Gains	4,891	3,038
Gross Unrealized Losses	(17)	(567)
Fair Value	173,997	203,269
Trust preferred securities
Amortized cost and fair value of securities available for sale
Amortized Cost	12,245	12,359
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,859)	(1,726)
Fair Value	10,386	10,633
Other debt securities
Amortized cost and fair value of securities available for sale
Amortized Cost	47,651	44,046
Gross Unrealized Gains	1,440	192
Gross Unrealized Losses	(11)	(311)
Fair Value	49,080	43,927
Government agency mortgage backed securities \| Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	600,257	621,690
Gross Unrealized Gains	7,694	719
Gross Unrealized Losses	(1,498)	(9,126)
Fair Value	606,453	613,283
Government agency mortgage backed securities \| Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	31,795	21,957
Gross Unrealized Gains	812	257
Gross Unrealized Losses	(62)	(384)
Fair Value	32,545	21,830
Government agency collateralized mortgage obligations \| Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	319,896	332,697
Gross Unrealized Gains	2,301	274
Gross Unrealized Losses	(986)	(5,982)
Fair Value	321,211	326,989
Government agency collateralized mortgage obligations \| Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	70,764	28,446
Gross Unrealized Gains	1,305	24
Gross Unrealized Losses	0	(135)
Fair Value	$ 72,069	$ 28,335

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
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