Share-Based Compensation - Restricted Stock Activity (Details) - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year (in shares)	302,940	154,134	55,000
Granted (in shares)	149,431	188,496	117,605
Exercised (in shares)	(57,373)	(3,512)	(4,722)
Cancelled/Forfeited (in shares)	(96,000)	(36,178)	(13,749)
Non-vested at end of year (in shares)	298,998	302,940	154,134
Non-vested, Weighted Average Grant Date Fair Value (in dollars per share)	$ 20.49	$ 18.17	$ 19.44	$ 14.00
Granted, Weighted average exercise price (in dollars per share)	23.75	17.22	21.19
Exercised, Weighted average exercise price (in dollars per share)	20.15	17.47	14.00
Canceled/Forfeited, Weighted average exercise price (in dollars per share)	$ 18.44	$ 18.72	$ 14.00
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year (in shares)	24,235	37,632	55,000
Granted (in shares)	0	0	0
Exercised (in shares)	(2,500)	(1,068)	(3,619)
Cancelled/Forfeited (in shares)	(12,118)	(12,329)	(13,749)
Non-vested at end of year (in shares)	9,617	24,235	37,632
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year (in shares)	169,580	70,172	0
Granted (in shares)	100,224	125,701	71,275
Exercised (in shares)	(27,976)	(2,444)	(1,103)
Cancelled/Forfeited (in shares)	(60,259)	(23,849)	0
Non-vested at end of year (in shares)	181,569	169,580	70,172
Performance restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at beginning of year (in shares)	109,125	46,330	0
Granted (in shares)	49,207	62,795	46,330
Exercised (in shares)	(26,897)	0	0
Cancelled/Forfeited (in shares)	(23,623)	0	0
Non-vested at end of year (in shares)	107,812	109,125	46,330

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ 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)(2)(iii)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target 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)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target 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)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ 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)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ 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)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ 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)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ 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)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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.

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