Stock Option and Compensation Plans - Schedule of Cash Proceeds From and Aggregate Intrinsic Value of Stock Options Exercised (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Cash proceeds from options exercised	$ 31	$ 768
Aggregate intrinsic value of options exercised	$ 37	$ 2,216

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration