Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current deferred tax assets:
Credit carryforwards	$ 251	$ 1,288
Net operating loss and other carryforwards	352	0
Allowance for doubtful accounts	1,447	1,066
Accrued liabilities	4,236	4,961
Subtotal	6,286	7,315
Less valuation allowance	(242)	(298)
Total current deferred tax assets	6,044	7,017
Current deferred tax liabilities:
Prepaid expenses	(739)	(976)
Net deferred tax assets, current	5,305	6,041
Noncurrent deferred tax assets:
Net operating loss and other carryforwards	1,365	1,720
Credit carryforwards	964	0
Deferred lease costs	356	416
Depreciation	(2,036)	(2,589)
Tax goodwill and intangibles	(739)	(469)
Stock-based compensation	1,238	1,242
Accrued rent	4,538	4,582
Impairment of long-lived assets	659	656
Interest rate swap	564	579
Noncurrent self-insurance liabilities	6,062	4,785
Subtotal	12,971	10,922
Less valuation allowance	(619)	(570)
Total noncurrent deferred tax assets	$ 12,352	$ 10,352