Stock Based Compensation - Textual (Details) - USD ($)	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Share-based Payment Arrangement [Abstract]
Stock-based compensation expense	$ 6,249,000	$ 6,504,000
Unrecognized stock-based compensation expense related to stock options	0
Unrecognized stock-based compensation expense related to non-vested stock awards	$ 18,759,000
Period unrecognized expenses is expected to be recognized	1 year 10 months 24 days
Intrinsic value of stock options outstanding	$ 608,000
Intrinsic value of stock options exercisable	$ 606,000
Share price (in dollars per share)	$ 23.26
Stock options exercised	$ 5,000	$ 1,180,000
Stock options granted	0	0

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
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-Name Accounting Standards Codification
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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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-Publisher FASB
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-SubTopic 10
-Section 50
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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Price of a single share of a number of saleable stocks of a company.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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