Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 item	Mar. 31, 2013
Income Taxes
Changes to the returns as originally filed			$ 0
Returns currently under examination		0
Deferred expense:
Federal	2,823	4,339
State	670	1,192
Total deferred expense	3,493	5,531
Total provision for income taxes	$ 3,493	$ 5,531
Reconciliation of the entity's provision for income taxes at statutory rates to the provision for income taxes at the entity's effective tax rate
Federal income tax statutory rate (as a percent)	35.00%	35.00%
Less: rate attributable to non-controlling interest members (as a percent)	(26.30%)	(31.60%)
State income taxes, net of federal benefit (as a percent)	1.20%	0.60%
Other (as a percent)	0.00%	0.00%
Valuation allowance (as a percent)	0.00%	0.00%
Effective tax rate (as a percent)	9.90%	4.00%