Segments and Related Information (Reconciliation of Total Segment Assets to Total Consolidated Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Asset Reconciliation:
Total assets	$ 3,563,980	$ 3,465,901	$ 3,388,828	$ 3,005,466	$ 2,923,198	$ 2,416,300
Total assets of discontinued operations	0				12,500	26,200
Continuing Operations [Member]
Asset Reconciliation:
Total assets	$ 3,564,000				$ 2,910,700	$ 2,390,100