Disclosures About Fair Value of Financial Instruments - Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financial assets:
Available-for-sale securities	$ 197,401	$ 276,021
Level 1 [Member]
Financial assets:
Available-for-sale securities	20,050	74,974
Level 2 [Member]
Financial assets:
Available-for-sale securities	177,351	201,047
Recurring [Member]
Financial assets:
Available-for-sale securities	197,401	276,021
Recurring [Member] | Interest Rate Swap
Financial assets:
Derivative asset	4,339	1,528
Financial Liabilities:
Derivative liability	4,583	1,612
Recurring [Member] | Interest Rate Cap
Financial assets:
Derivative asset	2	25
Financial Liabilities:
Derivative liability	2	25
Recurring [Member] | Level 1 [Member]
Financial assets:
Available-for-sale securities	20,050	74,974
Recurring [Member] | Level 2 [Member]
Financial assets:
Available-for-sale securities	177,351	201,047
Recurring [Member] | Level 2 [Member] | Interest Rate Swap
Financial assets:
Derivative asset	4,339	1,528
Financial Liabilities:
Derivative liability	4,583	1,612
Recurring [Member] | Level 2 [Member] | Interest Rate Cap
Financial assets:
Derivative asset	2	25
Financial Liabilities:
Derivative liability	$ 2	$ 25