NOTES PAYABLE AND COMMERCIAL BANK FINANCING: (Details) (Subsequent Event, USD $) In Millions, unless otherwise specified	0 Months Ended
	Jul. 23, 2014 5.625% Senior Unsecured Notes, due 2024	Jul. 23, 2014 5.625% Senior Unsecured Notes, due 2024 Period prior to August 1, 2019	Jul. 31, 2014 Term Loan B, due 2021 Bank Credit Agreement	Jul. 31, 2014 Term Loan B, due 2021 Bank Credit Agreement LIBOR	Jul. 31, 2014 Term Loan A Bank Credit Agreement	Jul. 31, 2014 Delayed draw term loan A Bank Credit Agreement	Jul. 31, 2014 Revolving commitments Bank Credit Agreement
Notes Payable And Commercial Bank Financing
Amount of debt issued	$ 550.0		$ 400.0
Debt instrument, stated interest rate payable (as a percent)	5.625%
Percentage of par value at which debt was issued	100.00%		99.75%
Redemption price of the debt instrument (as a percent)		100.00%
Maximum percentage of the principal amount of the debt instrument which the entity may redeem with the proceeds from certain equity offerings		35.00%
Variable rate basis				LIBOR
Interest rate margin (as a percent)				2.75%
LIBOR floor (as a percent)				0.75%
Amount of debt converted into revolving commitments					327.7	72.5
Remaining borrowing capacity before conversion of debt						108.2
Borrowing capacity					361.2	325.5
Remaining borrowing capacity after conversion of debt						35.7
Outstanding revolving commitments							485.2
Deferred financing costs related to amendment	$ 14.6