Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Comprehensive (loss) income:
Beginning Balance			$ 234,700	$ 202,531
Comprehensive Income
Net (loss) income	3,808	(375)	(196,685)	18,850
Total comprehensive income (loss)	3,808	(375)	(196,685)	18,850
Income tax benefits associated with the exercise of non-qualified stock options			(330)
Equity-based compensation expense			5,984	5,722
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors			2,456	2,420
Minority interest capital contribution			1,600
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests				(1,113)
Distribution to partnership interests			(563)	(685)
Treasury shares:
Stock Repurchased During Period, Value				(4,974)
Treasury Stock, Value, Acquired, Cost Method			(283)
Ending Balance	46,879	222,751	46,879	222,751
Common Stock [Member]
Comprehensive (loss) income:
Shares, Beginning Balance			32,009,286	31,435,264
Beginning Balance			3,201	3,144
Comprehensive Income
Net (loss) income			0	0
Total comprehensive income (loss)			0	0
Income tax benefits associated with the exercise of non-qualified stock options			0
Equity-based compensation expense			0	0
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors, Shares			640,805	391,177
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors			64	39
Minority interest capital contribution			0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests				0
Distribution to partnership interests			0	0
Treasury shares:
Stock Repurchased During Period, Value				0
Treasury Stock, Shares, Acquired			25,801
Treasury Stock, Value, Acquired, Cost Method			3
Shares, Ending Balance	32,675,892	31,826,441	32,675,892	31,826,441
Ending Balance	3,268	3,183	3,268	3,183
Additional Paid-in Capital [Member]
Comprehensive (loss) income:
Beginning Balance			399,148	387,803
Comprehensive Income
Net (loss) income			0	0
Total comprehensive income (loss)			0	0
Income tax benefits associated with the exercise of non-qualified stock options			(330)
Equity-based compensation expense			5,984	5,722
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors			2,392	2,381
Minority interest capital contribution			0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests				0
Distribution to partnership interests			0	0
Treasury shares:
Stock Repurchased During Period, Value				0
Treasury Stock, Value, Acquired, Cost Method			0
Ending Balance	407,194	395,906	407,194	395,906
Retained Earnings / Accumulated (deficit) [Member]
Comprehensive (loss) income:
Beginning Balance			(151,335)	(178,131)
Comprehensive Income
Net (loss) income			(197,110)	18,226
Total comprehensive income (loss)			(197,110)	18,226
Income tax benefits associated with the exercise of non-qualified stock options			0
Equity-based compensation expense			0	0
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors			0	0
Minority interest capital contribution			0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests				0
Distribution to partnership interests			0	0
Treasury shares:
Stock Repurchased During Period, Value				0
Treasury Stock, Value, Acquired, Cost Method			0
Ending Balance	(348,445)	(159,905)	(348,445)	(159,905)
Treasury Stock [Member]
Comprehensive (loss) income:
Beginning Balance			(17,852)	(12,878)
Comprehensive Income
Net (loss) income			0	0
Total comprehensive income (loss)			0	0
Income tax benefits associated with the exercise of non-qualified stock options			0
Equity-based compensation expense			0	0
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors			0	0
Minority interest capital contribution			0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests				0
Distribution to partnership interests			0	0
Treasury shares:
Stock Repurchased During Period, Value				(4,974)
Treasury Stock, Value, Acquired, Cost Method			(286)
Ending Balance	(18,138)	(17,852)	(18,138)	(17,852)
Noncontrolling Interests [Member]
Comprehensive (loss) income:
Beginning Balance			1,538	2,593
Comprehensive Income
Net (loss) income			425	624
Total comprehensive income (loss)			425	624
Income tax benefits associated with the exercise of non-qualified stock options			0
Equity-based compensation expense			0	0
Net issuance of stock upon exercise of stock options and under stock plans for employees and directors			0	0
Minority interest capital contribution			1,600
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests				(1,113)
Distribution to partnership interests			(563)	(685)
Treasury shares:
Stock Repurchased During Period, Value				0
Treasury Stock, Value, Acquired, Cost Method			0
Ending Balance	$ 3,000	$ 1,419	$ 3,000	$ 1,419