Fair Value Measurements - Schedule of Fair Values of Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 27,867	$ 22,393
Interest rate swap assets (included in "other assets")	1,375	139
Total assets	29,242	22,532
Interest rate swap liabilities (included in "other liabilities")	1,726	22,446
Total liabilities	1,726	22,446
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	27,867	22,393
Total assets	27,867	22,393
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate swap assets (included in "other assets")	1,375	139
Total assets	1,375	139
Interest rate swap liabilities (included in "other liabilities")	1,726	22,446
Total liabilities	$ 1,726	$ 22,446