Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Commitments and Contingencies - Additional Information - Legal Proceedings and Claims - Class Action Complaint (Details) - $ / shares	1 Months Ended		3 Months Ended			6 Months Ended
	Dec. 31, 2015	Sep. 30, 2014	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2017	Jun. 30, 2016
Loss Contingencies [Line Items]
Quarterly dividend (in usd per share)			$ 0.055	$ 0.055		$ 0.11	$ 0.11
Class Action Complaint
Loss Contingencies [Line Items]
Quarterly dividend (in usd per share)	$ 0.055	$ 0.55			$ 0.55