Stock-Based Employee Benefit Plans - Changes in Unvested Performance Shares, Restricted Stock Units and Non-Employee Director Restricted Stock Units (Parenthetical) (Details)	12 Months Ended
Dec. 31, 2015 shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Restricted stock units granted to non-employee directors	135,000
Additional common stock shares issued	131,212

The number of shares or units of entity securities issued in the transaction in which equity securities were issued to pay for goods or nonemployee services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=51659978&loc=d3e25284-112666

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)(iv)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration