Business Segments and Enterprise-Wide Information (Schedule of Revenue and Long-Lived Assets by Geographic Location) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 2,193,211	$ 2,291,586	$ 2,299,785
Long-Lived Assets	862,583	1,060,697	1,178,630
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,145,887	2,242,753	2,254,790
Long-Lived Assets	848,450	1,027,271	1,140,224
Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	47,324	48,833	44,995
Long-Lived Assets	$ 14,133	$ 33,426	$ 38,406