Stock-Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	$ 4,087		$ 4,087
Post-Tax	424	$ 196	1,171	$ 581
Pre-Tax	536	248	1,482	736
Director
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	424		424
Post-Tax	141	299	640	743
Pre-Tax	$ 178	$ 379	$ 810	$ 940

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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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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