Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2011	$ 829,247	$ 471	$ 244,211	$ (82,177)	$ (85)	$ 666,827
Balance (Share) at Dec. 31, 2011		47,194
Issuance of common units by the Partnership to non-controlling						232,791
Stock-based compensation	7,695	0	3,641	0	0	4,054
Common dividends	(17,078)	0	0	(17,078)	0	0
Net income	(13,986)	0	0	(6,810)	0	(7,176)
Conversion of restricted stock, net of shares withheld for taxes	(794)	2	(796)	0	0	0
Conversion of restricted stock, net of shares withheld for taxes (Shares)		206
Hedging gains or losses reclassified to earnings	162		0	0	(10)	(152)
Adjustment in fair value of derivatives	1,417		0	0	274	1,143
Non-controlling partner's impact of conversion of restricted units and options exercise	(680)	0	0	0	0	(680)
Distribution to non-controlling interest	(52,536)	0	0	0	0	(52,536)
Changes in equity due to issuance of units by the Partnership	11,126		27,019			(15,893)
Balance at Sep. 30, 2012	$ 997,040	$ 473	$ 274,075	$ (106,065)	$ 179	$ 828,378
Balance (Share) at Sep. 30, 2012		47,400