Business Segments, Concentration of Business, and Credit Risk and Significant Customers (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Total assets for reportable segments	$ 1,064,204	$ 1,259,729
Unallocated cash and cash equivalents	245,088	237,125	64,591	110,247
Consolidated total assets	1,064,204	1,259,729
Reportable segments
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Total assets for reportable segments	654,679	801,796
Consolidated total assets	654,679	801,796
Unallocated to Segments
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Unallocated cash and cash equivalents	245,088	237,125
Unallocated deferred tax assets	38,933	35,632
Other unallocated corporate assets	$ 125,504	$ 185,176