Income Taxes (Deferred Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred Taxes Assets [Abstract]
Allowance for uncollectible accounts	$ 897	$ 884
Accrued assets and other	5,292	5,212
Valuation allowances	(2,021)	(2,084)
Total current deferred tax assets	4,168	4,012
Share-based compensation	7,635	9,500
Interest on unrecognized tax benefits	230	363
Accrued liabilities and other	3,629	3,077
Operating and capital loss carryforwards	9,185	9,169
Valuation allowances	(7,665)	(7,265)
Total non-current deferred tax assets	13,014	14,844
Total deferred tax assets	17,182	18,856
Deferred Tax Liabilities [Abstract]
Prepaid expenses	1,071	925
Property and equipment, principally due to differences in depreciation	4,137	3,997
Goodwill, principally due to differences in amortization	184,897	148,494
Total deferred tax liabilities	190,105	153,416
Total deferred tax liabilities	$ 172,923	$ 134,560