Stockholders' Equity - Nonvested Restricted Stock Awards (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
Apr. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CDMI
Nonvested restricted stock awards and units
Number of restricted stock purchased by certain principal owners of the acquiree	1,433,946
AFSC
Nonvested restricted stock awards and units
Number of restricted stock purchased by certain principal owners of the acquiree		60,069
Restricted stock awards
Nonvested restricted stock awards and units
Outstanding, beginning of period (in shares)		1,109,622	1,626,827	192,165
Awarded (in shares)		77,744	20,115	1,451,231
Vested (in shares)		(571,894)	(537,320)	(16,569)
Outstanding, end of period (in shares)		615,472	1,109,622	1,626,827
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share)		$ 57.88	$ 57.66	$ 56.59
Awarded (in dollars per share)		65.52	67.12	57.75
Vested (in dollars per share)		58.03	57.56	52.82
Outstanding, end of period (in dollars per share)		$ 58.71	$ 57.88	$ 57.66
Unrecognized compensation expense		$ 18.1
Unrecognized compensation expense, period of recognition		11 months 5 days
Restricted stock awards \| CDMI
Nonvested restricted stock awards and units
Number of restricted stock purchased by certain principal owners of the acquiree				1,433,946
Restricted stock awards \| AFSC
Nonvested restricted stock awards and units
Number of restricted stock purchased by certain principal owners of the acquiree		60,069
Restricted Stock Units (RSUs)
Nonvested restricted stock awards and units
Outstanding, beginning of period (in shares)		231,088	156,695	194,913
Awarded (in shares)		51,521	187,272	76,306
Vested (in shares)		(53,839)	(79,036)	(91,510)
Forfeited (in shares)		(28,592)	(33,843)	(23,014)
Outstanding, end of period (in shares)		200,178	231,088	156,695
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share)		$ 61.53	$ 54.88	$ 50.21
Awarded (in dollars per share)		64.87	63.42	60.39
Vested (in dollars per share)		63.32	52.82	49.53
Forfeited (in dollars per share)		63.34	61.54	54.86
Outstanding, end of period (in dollars per share)		$ 61.65	$ 61.53	$ 54.88
Unrecognized compensation expense		$ 5.8
Unrecognized compensation expense, period of recognition		1 year 6 months 7 days

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

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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Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

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-Publisher FASB
-Name Accounting Standards Codification
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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.

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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

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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

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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.

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-Publisher FASB
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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

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

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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.

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