LONG-TERM DEBT: (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Senior Bank Term Debt [Member]	Dec. 31, 2012 Senior Bank Term Debt [Member]	Mar. 31, 2013 Senior Subordinated Notes [Member]	Mar. 31, 2013 Senior Subordinated Notes [Member] February 2013 [Member]	Dec. 31, 2012 Senior Subordinated Notes [Member] February 2013 [Member]	Mar. 31, 2013 Senior Subordinated Notes [Member] May 2016 [Member]	Dec. 31, 2012 Senior Subordinated Notes [Member] May 2016 [Member]	Mar. 31, 2013 Senior Notes [Member]	Dec. 31, 2012 Senior Notes [Member]	Dec. 31, 2011 Senior Notes [Member]	Mar. 31, 2013 Senior Notes [Member] March 2016 [Member]	Dec. 31, 2012 Senior Notes [Member] March 2016 [Member]
Total Debt	$ 822,370	$ 824,078	$ 376,336	$ 377,297	$ 327,034	$ 0	$ 747	$ 327,034	$ 327,034	$ 119,000	$ 119,000	$ 119,000	$ 119,000	$ 119,000
Less: current portion	3,840	4,587
Less: original issue discount	4,994	5,360
Long-term debt, net	$ 813,536	$ 814,131