Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			155,297
Stock based-awards			11,562
Repurchase of common shares			(7,388)
Dividends paid			(48,590)
Non-controlling interest dividends			(27)
Amortization of deferred pension costs, net of tax			136
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	$ (90)	$ (372)	71	$ (1,261)
Net income	22,709	16,535	40,391	31,652
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	19	$ (89)	43	$ (54)
Ending balance	151,452		151,452
Common Shares [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			0
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
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			0
Net income			0
Ending balance	1,148		1,148
Additional Paid-In Capital [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			84
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			52,850
Stock based-awards			6,109
Repurchase of common shares			0
Dividends paid			0
Non-controlling interest dividends			0
Amortization of deferred pension costs, net of tax			0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			0
Net income			0
Ending balance	59,043		59,043
Retained Earnings [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			(84)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			187,957
Stock based-awards			0
Repurchase of common shares			0
Dividends paid			(48,590)
Non-controlling interest dividends			0
Amortization of deferred pension costs, net of tax			0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			0
Net income			40,348
Ending balance	179,631		179,631
Accumulated Other Comprehensive Income (Loss) [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(9,828)
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			136
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			71
Net income			0
Ending balance	(9,621)		(9,621)
Treasury Stock [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(80,773)
Stock based-awards			5,453
Repurchase of common shares			(7,388)
Dividends paid			0
Non-controlling interest dividends			0
Amortization of deferred pension costs, net of tax			0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			0
Net income			0
Ending balance	(82,708)		(82,708)
Non-Controlling Interests [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			3,943
Stock based-awards			0
Repurchase of common shares			0
Dividends paid			0
Non-controlling interest dividends			(27)
Amortization of deferred pension costs, net of tax			0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			0
Ending balance	$ 3,959		$ 3,959