ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS): (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated other comprehensive income (loss)
Balance at the beginning of the period			$ (4,020)	$ 1,390
Other comprehensive income/loss before reclassifications			3,017	599
Amounts reclassified from accumulated other comprehensive income/loss			3,027	(1,268)
Net current-period other comprehensive income/loss, net of taxes	$ 5,219	$ 51	6,044	(669)
Balance at the end of the period	2,024	721	2,024	721
Unrealized Gains / Losses on Available-for-Sale Securities
Accumulated other comprehensive income (loss)
Balance at the beginning of the period			(374)	(6)
Other comprehensive income/loss before reclassifications			195	6
Amounts reclassified from accumulated other comprehensive income/loss			17	10
Net current-period other comprehensive income/loss, net of taxes			212	16
Balance at the end of the period	(162)	10	(162)	10
Gains / Losses on Derivatives
Accumulated other comprehensive income (loss)
Balance at the beginning of the period			(3,646)	1,396
Other comprehensive income/loss before reclassifications			2,822	593
Amounts reclassified from accumulated other comprehensive income/loss			3,010	(1,278)
Net current-period other comprehensive income/loss, net of taxes			5,832	(685)
Balance at the end of the period	$ 2,186	$ 711	$ 2,186	$ 711