CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common stock	Treasury stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive income (AOCI)	Non- controlling interests
Beginning balance at Dec. 31, 2014	$ 448,756	$ 46	$ (53,807)	$ 3,553,430	$ (3,069,241)	$ 40	$ 18,288
Beginning balance (in shares) at Dec. 31, 2014		46,405,000	5,892,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-based compensation expense related to stock appreciation rights (SARs) and stock options	398			398
Equity-based compensation related to deferred stock units (DSUs)	234			234
Equity-based compensation related to restricted stock (RS)	23,120			23,120
Issuance of DSUs	82			82
Issuance of DSUs (in shares)		94,000
Issuance of RS, net of forfeitures primarily related to satisfying tax withholdings	(4,170)	$ 1		(4,171)
Issuance of RS, net of forfeitures primarily related to satisfying tax withholdings (in shares)		253,000
Exercise of SARs and stock options, net of forfeitures related to satisfying tax withholdings	(100)			(100)
Exercise of SARs and stock options, net of forfeitures related to satisfying tax withholdings (in shares)		11,000
Impact of redeemable noncontrolling interests accretion	(4,704)			(4,704)
Impact of subsidiary equity transactions	(4,803)			(4,441)			(362)
Repurchase of common stock	$ (1,702)		$ (1,702)
Repurchase of common stock (in shares)	(5,598,094)		(96,000)
Net income (loss)	$ (99,140)				(96,080)		(3,060)
Ending balance at Dec. 31, 2015	357,971	$ 47	$ (55,509)	3,563,848	(3,165,321)	40	14,866
Ending balance (in shares) at Dec. 31, 2015		46,763,000	5,988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-based compensation expense related to stock appreciation rights (SARs) and stock options	128			128
Equity-based compensation related to deferred stock units (DSUs)	341			341
Equity-based compensation related to restricted stock (RS)	11,390			11,390
Issuance of DSUs	0			0
Issuance of DSUs (in shares)		0
Issuance of RS, net of forfeitures primarily related to satisfying tax withholdings	(1,574)	$ 0		(1,574)
Issuance of RS, net of forfeitures primarily related to satisfying tax withholdings (in shares)		(267,000)
Exercise of SARs and stock options, net of forfeitures related to satisfying tax withholdings	(254)			(254)
Exercise of SARs and stock options, net of forfeitures related to satisfying tax withholdings (in shares)		27,000
Impact of redeemable noncontrolling interests accretion	(599)			(599)
Impact of subsidiary equity transactions	5,719			4,924		59	736
Repurchase of common stock	$ (74,265)		$ (74,265)
Repurchase of common stock (in shares)	(2,175,268)		(5,598,000)
Net income (loss)	$ 66,627				70,085		(3,458)
Ending balance at Dec. 31, 2016	365,484	$ 47	$ (129,774)	3,578,204	(3,095,236)	99	12,144
Ending balance (in shares) at Dec. 31, 2016		46,523,000	11,586,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-based compensation expense related to stock appreciation rights (SARs) and stock options	118			118
Equity-based compensation related to deferred stock units (DSUs)	430			430
Equity-based compensation related to restricted stock (RS)	14,683			14,683
Issuance of RS, net of forfeitures primarily related to satisfying tax withholdings	(15,965)	$ (1)		(15,964)
Issuance of RS, net of forfeitures primarily related to satisfying tax withholdings (in shares)		(882,000)
Exercise of SARs and stock options, net of forfeitures related to satisfying tax withholdings	(1)			(1)
Exercise of SARs and stock options, net of forfeitures related to satisfying tax withholdings (in shares)		0
Impact of redeemable noncontrolling interests accretion	2,121			2,121
Impact of subsidiary equity transactions	(8,186)			2,338		(99)	(10,425)
Repurchase of common stock	(30,434)		$ (30,434)
Repurchase of common stock (in shares)			(2,176,000)
Net income (loss)	172,239			0	173,958		(1,719)
Ending balance at Dec. 31, 2017	$ 500,489	$ 46	$ (160,208)	$ 3,581,929	$ (2,921,278)	$ 0	$ 0
Ending balance (in shares) at Dec. 31, 2017		45,641,000	13,762,000