The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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.

+ References

No definition available.

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Employee Benefit Plans - Options Outstanding by Exercise Price Range (Details) - Officer and Employee Plans [Member] - $ / shares	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 11.78	$ 10.57	$ 10.62
Number Outstanding (in shares)	225,442	717,524	817,414
Options Outstanding, Weighted Average Remaining Life	5 years 1 month 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.78
Options, Number Exercisable (in shares)	186,801
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 11.11
6.20 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 6.20
Number Outstanding (in shares)	750
Options Outstanding, Weighted Average Remaining Life	4 years 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.20
Options, Number Exercisable (in shares)	750
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 6.20
6.60 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 6.60
Number Outstanding (in shares)	41,500
Options Outstanding, Weighted Average Remaining Life	5 years 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.60
Options, Number Exercisable (in shares)	41,500
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 6.60
6.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 6.80
Number Outstanding (in shares)	19,375
Options Outstanding, Weighted Average Remaining Life	3 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.80
Options, Number Exercisable (in shares)	19,375
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 6.80
9.48 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 9.48
Number Outstanding (in shares)	29,375
Options Outstanding, Weighted Average Remaining Life	5 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.48
Options, Number Exercisable (in shares)	29,375
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.48
9.52 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 9.52
Number Outstanding (in shares)	525
Options Outstanding, Weighted Average Remaining Life	3 months 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.52
Options, Number Exercisable (in shares)	525
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.52
9.60 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 9.60
Number Outstanding (in shares)	37,625
Options Outstanding, Weighted Average Remaining Life	6 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.60
Options, Number Exercisable (in shares)	37,625
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.60
10.48 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 10.48
Number Outstanding (in shares)	20,513
Options Outstanding, Weighted Average Remaining Life	4 months 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.48
Options, Number Exercisable (in shares)	20,513
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 10.48
11.67 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 11.67
Number Outstanding (in shares)	3,250
Options Outstanding, Weighted Average Remaining Life	3 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.67
Options, Number Exercisable (in shares)	3,250
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 11.67
14.40 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 14.40
Number Outstanding (in shares)	15,180
Options Outstanding, Weighted Average Remaining Life	1 year 10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 14.40
Options, Number Exercisable (in shares)	15,180
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 14.40
15.05 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 15.05
Number Outstanding (in shares)	42,745
Options Outstanding, Weighted Average Remaining Life	8 years 5 months 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.05
Options, Number Exercisable (in shares)	4,104
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.05
31.96 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 31.96
Number Outstanding (in shares)	13,916
Options Outstanding, Weighted Average Remaining Life	10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 31.96
Options, Number Exercisable (in shares)	13,916
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 31.96
60.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices (in dollars per share)	$ 60.80
Number Outstanding (in shares)	688
Options Outstanding, Weighted Average Remaining Life	1 month 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 60.80
Options, Number Exercisable (in shares)	688
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 60.80