Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 178,806us-gaap_ProfitLoss	$ 152,588us-gaap_ProfitLoss	$ 155,434us-gaap_ProfitLoss
Foreign currency translation adjustments	(32,096)	(23,292)	5,892
Reclassification of foreign currency translation adjustments to discontinued operations	3,114	0	0
Total comprehensive income	149,824	129,296	161,326
Total comprehensive income attributable to noncontrolling interests	(6,382)	(5,240)	(1,616)
Total comprehensive income attributable to common stockholders	$ 143,442us-gaap_ComprehensiveIncomeNetOfTax	$ 124,056us-gaap_ComprehensiveIncomeNetOfTax	$ 159,710us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for translation gain (loss) realized upon the sale or liquidation of an investment in a foreign entity and foreign currency hedges that are designated and qualified as hedging instruments for hedges of the foreign currency exposure of a net investment in a foreign operation.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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