Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 148,732
Stock based-awards	6,291
Repurchase of common shares	(3,310)
Dividends paid	(24,322)
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	48
Interest rate swaps, net of tax	560
Net income	23,577	$ 17,682
Ending balance	151,576
Common Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,148
Stock based-awards	0
Repurchase of common shares	0
Dividends paid	0
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	0
Interest rate swaps, net of tax	0
Net income	0
Ending balance	1,148
Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	54,463
Stock based-awards	1,207
Repurchase of common shares	0
Dividends paid	0
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	0
Interest rate swaps, net of tax	0
Net income	0
Ending balance	55,670
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	173,855
Stock based-awards	0
Repurchase of common shares	0
Dividends paid	(24,322)
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	0
Interest rate swaps, net of tax	0
Net income	23,527
Ending balance	173,060
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(8,353)
Stock based-awards	0
Repurchase of common shares	0
Dividends paid	0
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	48
Interest rate swaps, net of tax	560
Net income	0
Ending balance	(7,745)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(76,269)
Stock based-awards	5,084
Repurchase of common shares	(3,310)
Dividends paid	0
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	0
Interest rate swaps, net of tax	0
Net income	0
Ending balance	(74,495)
Non-Controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	3,888
Stock based-awards	0
Repurchase of common shares	0
Dividends paid	0
Non-controlling interest dividends	0
Amortization of deferred pension costs, net of tax	0
Interest rate swaps, net of tax	0
Net income	50
Ending balance	$ 3,938