Business acquisition number of share offered for each share of acquiree entity.

No definition available.

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- Definition

Business acquisition shareholders entitled to receive cash for each share.

+ References

No definition available.

+ Details

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- Definition

Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Fair Value, Per Share

+ References

No definition available.

+ Details

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- Definition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Allowance for Loan Losses

+ References

No definition available.

+ Details

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- Definition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loan Discount

+ References

No definition available.

+ Details

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- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- Definition

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.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the fair value of the receivables acquired, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

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Period Type:	instant

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=73531572&loc=d3e1043-128460

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
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Balance Type:	credit
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- Definition

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to property, plant, and equipment acquired in connection with a business combination for which the initial accounting was incomplete.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 4A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=SL65897772-128472

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Period Type:	duration

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
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-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
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-Subparagraph (g)
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- Definition

Amount of (increase) decrease to an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from the subsequent recognition of deferred tax assets.

+ References

+ Details

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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-Publisher FASB
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-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

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Business Combinations - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 04, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 04, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 291,670,000		$ 291,670,000			$ 291,764,000
Merger related expenses		0	$ 0	0	$ 3,167,000
Integrity Bancshares, Inc.
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired	100.00%
Business acquisition, cash per share offered in exchange of share (in dollars per share)	$ 52.50
Shares of S&T offered for each share of Integrity (shares)	2.0627
Fair value of total consideration	$ 172,000,000					$ 171,979,000
Cash	$ 29,500,000					29,510,000
S&T common shares issued (shares)	4,933,115
S&T common shares issued, fair value (in dollars per share)	$ 28.88
Purchase accounting adjustments, increase to goodwill						1,100,000
Purchase accounting adjustments, decrease to deferred taxes						300,000
Goodwill						115,850,000
Carryover of allowance for loan losses	$ 0
Fair value of loans acquired	788,700,000					788,687,000
Discount on loans acquired	14,800,000
Merger related expenses		$ 0	$ 0	$ 0	$ 3,200,000
Integrity Bancshares, Inc. \| Commercial and Industrial
Business Acquisition [Line Items]
Fair value of loans acquired	184,200,000
Integrity Bancshares, Inc. \| Commercial Real Estate
Business Acquisition [Line Items]
Fair value of loans acquired	331,600,000
Integrity Bancshares, Inc. \| Commercial Construction
Business Acquisition [Line Items]
Fair value of loans acquired	92,400,000
Integrity Bancshares, Inc. \| Residential Mortgage
Business Acquisition [Line Items]
Fair value of loans acquired	116,900,000
Integrity Bancshares, Inc. \| Home Equity
Business Acquisition [Line Items]
Fair value of loans acquired	25,600,000
Integrity Bancshares, Inc. \| Installment and Other Consumer
Business Acquisition [Line Items]
Fair value of loans acquired	36,100,000
Integrity Bancshares, Inc. \| Consumer Construction
Business Acquisition [Line Items]
Fair value of loans acquired	$ 1,900,000
Integrity Bancshares, Inc. \| Land
Business Acquisition [Line Items]
Purchase accounting adjustments, decrease to land						$ 800,000