Number of institutions issuing debt.

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Number of securities representing interests in tranches of trusts.

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No definition available.

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

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The fair value of available-for-sale securities that serve as collateral for borrowings.

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For any transfer of securities categorized as held-to-maturity, this item represents the net carrying amount of the transferred security to another category of investments in debt and equity securities (trading or available-for-sale).

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This item represents the unrealized gain (loss) recognized in other comprehensive income (a separate component of shareholders' equity) as a result of securities categorized as held-to-maturity being transferred to the available-for-sale securities category.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Securities - Narrative (Details)	3 Months Ended		9 Months Ended
Securities - Narrative (Details)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) security institution	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Transferred security, at carrying value	$ 365,941,000		$ 365,941,000
Unrealized gain (loss) on transfer	13,218,000
Gains on sales of securities available for sale, net	57,000	$ 0	57,000	$ 1,186,000
Amortized cost	1,141,627,000		1,141,627,000		$ 686,405,000
Gross gains on sales of securities available for sale	57,000	0	57,000	1,257,000
Securities available for sale	1,150,459,000		$ 1,150,459,000		674,248,000
Number of institutions issuing debt (more than) \| institution			160
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	12,454,000		$ 12,454,000		23,749,000
Securities available for sale	8,960,000		$ 8,960,000		18,389,000
Number of securities representing interests in tranches of trusts (tranches) \| security			2
Impairments			$ 0
Secure government, public and trust deposits
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	459,369,000		459,369,000		642,447,000
Short-term borrowings
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	27,164,000		27,164,000		24,426,000
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	9,346,000		9,346,000
Sale proceeds	9,403,000
Amortized cost	12,454,000		12,454,000		23,749,000
Securities available for sale	8,960,000		8,960,000		18,389,000
Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	2,946,000		2,946,000
Sale proceeds			2,946,000
Other equity securities
Schedule of Available-for-sale Securities [Line Items]
Sale proceeds				4,028,000
Amortized cost		$ 2,842,000		2,842,000
Gross gains on sales of securities available for sale				$ 1,186,000
Government agency mortgage backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	14,750,000		14,750,000
Government agency mortgage backed securities \| Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	459,336,000		459,336,000
Amortized cost	459,336,000		459,336,000		414,019,000
Securities available for sale	459,558,000		459,558,000		409,317,000
Government agency collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	16,395,000		16,395,000
Government agency collateralized mortgage obligations \| Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	234,224,000		234,224,000
Amortized cost	234,224,000		234,224,000		171,362,000
Securities available for sale	232,658,000		232,658,000		$ 168,826,000
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities	4,876,000		4,876,000
Amortized cost	337,725,000		337,725,000
Securities available for sale	$ 350,354,000		$ 350,354,000