Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measure at Fair Value (Details) - Recurring $ in Thousands	Jun. 30, 2017 USD ($)
Marketable securities
Recurring Fair Value Measurements:
Assets, fair value	$ 278,072
Level 1 \| Marketable securities
Recurring Fair Value Measurements:
Assets, fair value	278,072
Level 2 \| Marketable securities
Recurring Fair Value Measurements:
Assets, fair value	0
Level 3 \| Marketable securities
Recurring Fair Value Measurements:
Assets, fair value	0
Interest rate cap
Recurring Fair Value Measurements:
Assets, fair value	46
Interest rate cap \| Level 1
Recurring Fair Value Measurements:
Assets, fair value	0
Interest rate cap \| Level 2
Recurring Fair Value Measurements:
Assets, fair value	46
Interest rate cap \| Level 3
Recurring Fair Value Measurements:
Assets, fair value	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant