CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock Issued	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest [Member]
Balances at Dec. 31, 2012	$ 857,251	$ 140,080	$ (745,205)	$ 152,645	$ 1,671,117	$ (411,168)	$ 49,782
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(223,095)				(232,848)		9,753
Cash dividends declared:
Common @ $0.82 per share, $0.82 per share, and $0.666 per share in 2013, 2014, and 2015, respectively	(66,228)				(66,228)
Noncontrolling interests	(4,764)						(4,764)
Total other comprehensive income (loss), net of deferred income taxes of $(18,447), $20,264, and $(17,519) in 2013, 2014, and 2015 respectively	40,855					40,553	302
Contributions from noncontrolling interests	4,825						4,825
Purchase of subsidiary shares from noncontrolling interest	(185)			(292)			107
Noncontrolling interests transferred in the Infrastructure Transaction	(15,909)			1,003			(16,912)
Stock options exercised, net 20,000 shares 2013, respectively	400	25		375
Vesting of restricted stock units and other stock grants, net 74,297 shares, 130,925 shares and 31,147 shares in 2013, 2014 and 2015, respectively	1,185	143	(1,032)	2,074
Amortization of unearned stock-based compensation, net of forfeitures	3,220			3,220
Balances at Dec. 31, 2013	597,555	140,248	(746,237)	159,025	1,372,041	(370,615)	43,093
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(17,676)				(22,171)		4,495
Cash dividends declared:
Common @ $0.82 per share, $0.82 per share, and $0.666 per share in 2013, 2014, and 2015, respectively	(66,321)				(66,321)
Noncontrolling interests	(2,319)						(2,319)
Total other comprehensive income (loss), net of deferred income taxes of $(18,447), $20,264, and $(17,519) in 2013, 2014, and 2015 respectively	(163,243)					(161,641)	(1,602)
Contributions from noncontrolling interests	1,560						1,560
Noncontrolling interests transferred in the Infrastructure Transaction	(905)						(905)
Vesting of restricted stock units and other stock grants, net 74,297 shares, 130,925 shares and 31,147 shares in 2013, 2014 and 2015, respectively	1,551	196	(714)	2,069
Treasury shares repurchased, 150,000 and 596,632 shares in 2014 and 2015 respectively	(2,864)		(2,864)
Amortization of unearned stock-based compensation, net of forfeitures	4,572			4,572
Balances at Dec. 31, 2014	351,910	140,444	(749,815)	165,666	1,283,549	(532,256)	44,322
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	6,332				6,188		144
Cash dividends declared:
Common @ $0.82 per share, $0.82 per share, and $0.666 per share in 2013, 2014, and 2015, respectively	(53,382)				(53,382)
Noncontrolling interests	(4,498)						(4,498)
Total other comprehensive income (loss), net of deferred income taxes of $(18,447), $20,264, and $(17,519) in 2013, 2014, and 2015 respectively	13,928					16,568	(2,640)
Contributions from noncontrolling interests	2,100						2,100
Purchase of subsidiary shares from noncontrolling interest	(398)			(3)			(395)
Sale of investment in consolidated subsidiary	200						200
Vesting of restricted stock units and other stock grants, net 74,297 shares, 130,925 shares and 31,147 shares in 2013, 2014 and 2015, respectively	(304)	59	(264)	(99)
Treasury shares repurchased, 150,000 and 596,632 shares in 2014 and 2015 respectively	(10,220)		(10,220)
Amortization of unearned stock-based compensation, net of forfeitures	5,135			5,135
Balances at Dec. 31, 2015	$ 310,803	$ 140,503	$ (760,299)	$ 170,699	$ 1,236,355	$ (515,688)	$ 39,233