Amount of allowance for loan losses for collateral dependent impaired loans with specific reserves.

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Collateral dependent impaired loans which had specific reserves.

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The percentage of liquidation expenses estimated with liquidating impaired collateral.

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

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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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Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

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Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Fair value of financial and nonfinancial obligations.

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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Fair Value Measurements and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$ 0	$ 0	$ 0	$ 0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	$ 0	0	$ 0
AFS securities [Abstract]
AFS Securities	1,365,521		1,365,521		$ 1,338,290
Trading securities	10,406		10,406		9,259
Liabilities [Abstract]
Collateral dependent impaired financing receivable with specific reserves	800		800		7,000
Allowance for loan losses for collateral dependent impaired loans with specific reserves	500		$ 500		1,500
Minimum [Member]
Liabilities [Abstract]
Liquidation expense ratio on impaired collateral			10.00%
Maximum [Member]
Liabilities [Abstract]
Liquidation expense ratio on impaired collateral			35.00%
Federal Agency [Member]
AFS securities [Abstract]
AFS Securities	159,520		$ 159,520		174,408
State & Municipal [Member]
AFS securities [Abstract]
AFS Securities	44,020		44,020		46,726
Other Securities [Member]
AFS securities [Abstract]
AFS Securities	19,012		19,012		20,739
Recurring Basis [Member]
AFS securities [Abstract]
AFS Securities	1,365,521		1,365,521		1,338,290
Trading securities	10,406		10,406		9,259
Derivatives	5,631		5,631		3,210
Total	1,381,558		1,381,558		1,350,759
Liabilities [Abstract]
Derivatives	2,960		2,960		506
Total	2,960		2,960		506
Recurring Basis [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	10,744		10,744		11,493
Trading securities	10,406		10,406		9,259
Derivatives	0		0		0
Total	21,150		21,150		20,752
Liabilities [Abstract]
Derivatives	0		0		0
Total	0		0		0
Recurring Basis [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	1,354,777		1,354,777		1,326,797
Trading securities	0		0		0
Derivatives	5,631		5,631		3,210
Total	1,360,408		1,360,408		1,330,007
Liabilities [Abstract]
Derivatives	2,960		2,960		506
Total	2,960		2,960		506
Recurring Basis [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Trading securities	0		0		0
Derivatives	0		0		0
Total	0		0		0
Liabilities [Abstract]
Derivatives	0		0		0
Total	0		0		0
Recurring Basis [Member] \| Federal Agency [Member]
AFS securities [Abstract]
AFS Securities	159,520		159,520		174,408
Recurring Basis [Member] \| Federal Agency [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| Federal Agency [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	159,520		159,520		174,408
Recurring Basis [Member] \| Federal Agency [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| State & Municipal [Member]
AFS securities [Abstract]
AFS Securities	44,020		44,020		46,726
Recurring Basis [Member] \| State & Municipal [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| State & Municipal [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	44,020		44,020		46,726
Recurring Basis [Member] \| State & Municipal [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| Mortgage-Backed [Member]
AFS securities [Abstract]
AFS Securities	564,061		564,061		529,844
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	564,061		564,061		529,844
Recurring Basis [Member] \| Mortgage-Backed [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member]
AFS securities [Abstract]
AFS Securities	578,908		578,908		566,573
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	578,908		578,908		566,573
Recurring Basis [Member] \| Collateralized Mortgage Obligations [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	0		0		0
Recurring Basis [Member] \| Other Securities [Member]
AFS securities [Abstract]
AFS Securities	19,012		19,012		20,739
Recurring Basis [Member] \| Other Securities [Member] \| Level 1 [Member]
AFS securities [Abstract]
AFS Securities	10,744		10,744		11,493
Recurring Basis [Member] \| Other Securities [Member] \| Level 2 [Member]
AFS securities [Abstract]
AFS Securities	8,268		8,268		9,246
Recurring Basis [Member] \| Other Securities [Member] \| Level 3 [Member]
AFS securities [Abstract]
AFS Securities	$ 0		$ 0		$ 0