Summary of Significant Accounting Policies (Table)

12 Months Ended

Dec. 31, 2013

Summary of Significant Accounting Policies [Abstract]

Schedule of Change in Estimated Average Membership Life [Table Text Block]

	Estimated Average Membership Life of an Unrestricted Member			Estimated Average Membership Life of a Restricted Member
Period	2013	2012	2011	2013	2012	2011
Three months ended March 31	25 months	28 months	27 months	27 months	25 months	27 months
Three months ended June 30	24 months	28 months	27 months	28 months	27 months	27 months
Three months ended September 30	23 months	28 months	28 months	28 months	28 months	28 months
Three months ended December 31	23 months	27 months	29 months	28 months	27 months	24 months

Schedule of Accounts Receivable and Allowance for Doubtful Accounts

	Balance Beginning				Write-offs Net of		Balance at
	of the Year		Additions		Recoveries		End of Year
December 31, 2013	$	3,249	$	8,335	$	(9,275)	$	2,309
December 31, 2012	$	2,440	$	9,711	$	(8,902)	$	3,249
December 31, 2011	$	2,565	$	6,698	$	(6,823)	$	2,440

Schedule of Supplemental Disclosure of Cash Flow Information

		Year Ended December 31,
		2013		2012		2011
Cash paid
	Interest (net of amounts capitalized)	$	19,744	$	23,738	$	28,953
	Income taxes	$	390	$	924	$	617
Noncash investing and financing activities
	Acquisition of fixed assets included in accounts payable and accrued expenses	$	5,789	$	2,797	$	1,645
See Note 9 for additional noncash financing activities.

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

		For The Year Ended December 31,
		2013		2012		2011
Weighted average number of common share outstanding — basic			24,031,533		23,436,393		22,828,031
Effect of dilutive share-based awards			705,428		678,147		595,766
Weighted average number of common shares outstanding — diluted			24,736,961		24,114,540		23,423,797
Earnings per share:
	Basic	$	0.51	$	0.51	$	0.28
	Diluted	$	0.50	$	0.50	$	0.27

Schedule of Assumptions Used to Derive the Fair Value of Option Awards

	Risk-Free					Expected	Fair Value
	Interest		Expected	Expected		Dividend	at Date
Common	Rate		Life	Volatility		Yield	of Grant
2011 Grants	2.6	%	6 years	79	%	—	$	2.74
2012 option modification incremental expense	0.4	%	3 years	50	%	—		—