INCOME TAXES: (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012 item
Reconciliation of federal income taxes at the applicable statutory rate to the recorded provision from continuing operations
Federal statutory rate (as a percent)	35.00%	35.00%	35.00%
Amount of valuation allowance for deferred tax asset of consolidated VIEs released			$ 7,700,000
Number of variable interest entities for which the valuation allowance released			1
Adjustments-
State income taxes, net of federal tax benefit (as a percent)	(0.10%)	8.30%	(0.40%)
Non-deductible items (as a percent)	3.40%	1.40%	0.30%
Domestic Production Activities Deduction (as a percent)	(3.20%)	(3.80%)	(1.40%)
Effect of consolidated VIEs (as a percent)	0.80%	3.70%	(3.40%)
Change in state tax laws and rates (as a percent)	(0.10%)	(5.50%)	0.20%
Changes in unrecognized tax benefits (as a percent)	(3.40%)	0.80%	1.50%
Other (as a percent)	(0.90%)	0.10%	0.20%
Effective income tax rate (as a percent)	31.50%	40.00%	32.00%
Tax benefit related to domestic production activities deduction	800,000	2,000,000
Benefit related to expiration of the applicable statute of limitations	$ (8,285,000)