Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 93,993
Stock based-awards	5,208
Tax benefit of stock-based awards issued	(68)
Repurchase of common shares	(72,898)
Dividends paid	(23,940)
Amortization of deferred pension costs, net of tax	105
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(897)	0
Net income (loss)	31,042	61,153
Net income (loss) attributable to non-controlling interest	(357)	89
Ending balance	32,545
Common Shares [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,174
Stock based-awards	0
Tax benefit of stock-based awards issued	0
Repurchase of common shares	0
Dividends paid	0
Amortization of deferred pension costs, net of tax	0
Net income (loss)	0
Ending balance	1,174
Additional Paid-In Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	0
Stock based-awards	925
Tax benefit of stock-based awards issued	(68)
Repurchase of common shares	0
Dividends paid	0
Amortization of deferred pension costs, net of tax	0
Net income (loss)	0
Ending balance	857
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	415,906
Stock based-awards	0
Tax benefit of stock-based awards issued	0
Repurchase of common shares	0
Dividends paid	(23,940)
Amortization of deferred pension costs, net of tax	0
Net income (loss)	31,399
Ending balance	423,365
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(11,894)
Stock based-awards	0
Tax benefit of stock-based awards issued	0
Repurchase of common shares	0
Dividends paid	0
Amortization of deferred pension costs, net of tax	105
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(897)
Net income (loss)	0
Ending balance	(12,686)
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(317,613)
Stock based-awards	4,283
Tax benefit of stock-based awards issued	0
Repurchase of common shares	(72,898)
Dividends paid	0
Amortization of deferred pension costs, net of tax	0
Net income (loss)	0
Ending balance	(386,228)
Non-Controlling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	6,420
Stock based-awards	0
Tax benefit of stock-based awards issued	0
Repurchase of common shares	0
Dividends paid	0
Amortization of deferred pension costs, net of tax	0
Ending balance	$ 6,063