Lease Agreements - (Textual) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Leases [Abstract]
Operating Leases, Rent Expense	$ 14,173us-gaap_LeaseAndRentalExpense	$ 15,062us-gaap_LeaseAndRentalExpense	$ 15,579us-gaap_LeaseAndRentalExpense
Lease Extrication Charges	186cas_LeaseExtricationCharges	1,448cas_LeaseExtricationCharges	0cas_LeaseExtricationCharges
Capital Leased Assets, Gross	$ 2,452us-gaap_CapitalLeasedAssetsGross	$ 1,660us-gaap_CapitalLeasedAssetsGross

Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6455314&loc=d3e45014-112735

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