Other Significant Events (Details) $ in Thousands	12 Months Ended
Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014 USD ($) ft²	Dec. 31, 2013 USD ($) ft²	Jan. 31, 2014 ft²
Other Significant Noncash Transactions [Line Items]
Net Rentable Area \| ft²	1,046,394	1,471,319	200,306	79,000
Lease termination fee		$ 5,700
Amortization of Intangible Assets	$ 33,947	41,155	$ 47,395
Contract Termination [Member]
Other Significant Noncash Transactions [Line Items]
Amortization of Intangible Assets		$ 1,300

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

Name:	us-gaap_AmortizationOfIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration