SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Details 6) (Subsequent Event, Common Class A [Member], USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended
	Apr. 30, 2013	May 01, 2013
Subsequent Event | Common Class A [Member]
Subsequent Event [Line Items]
Shares issued under public offering	18.0
Period granted to underwriters to purchase additional shares	30 days
Number of shares granted to underwriters for purchase	2.7
Offering price (in dollars per share)		$ 27.25