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Short-term Borrowings (Details) - Outstanding Balances and Related Information of Short-term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Outstanding Balances and Related Information of Short-term Borrowings [Abstract]
Balance at year-end	$ 35,825	$ 14,808	$ 32,803
Average balance outstanding	11,768	8,379
Maximum month-end balance	$ 35,825	$ 19,970
Weighted-average rate at year-end	1.37%	0.98%
Weighted-average rate during the year	1.65%	1.77%

X

- Definition

Outstanding Balances And Related Information Of Short Term Borrowings [Abstract]

+ References

No definition available.

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- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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-Name Accounting Standards Codification
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-Topic 942
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-Section S99
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-Subparagraph (SX 210.9-03(13))
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Weighted average interest rate of short-term debt outstanding.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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